SNGX / Soligenix, Inc. - Документы SEC, Годовой отчет, Доверенное заявление

FDA Grants Soligenix Orphan Drug Designation for the Treatment of Behçet’s Disease after Reviewing Recent Phase 2 Clinical Study Results Provides SGX945 Seven Years of U.S. Market Exclusivity Upon FDA Approval

EXHIBIT 99.1 FDA Grants Soligenix Orphan Drug Designation for the Treatment of Behçet’s Disease after Reviewing Recent Phase 2 Clinical Study Results Provides SGX945 Seven Years of U.S. Market Exclusivity Upon FDA Approval PRINCETON, NJ – August 18, 2025 – Soligenix, Inc. (Nasdaq: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused on developing and commercializing pro

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): August 18, 2025 Commission File N

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): August 18, 2025 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of inc

Up to 1,054,688 Shares of Common Stock Issuable Upon the Exercise of Previously Issued Common Warrants

Prospectus Supplement No. 1 (To Prospectus dated March 21, 2025) Filed Pursuant to Rule 424(b)(3) Registration Statement No. 333-280993 Up to 1,054,688 Shares of Common Stock Issuable Upon the Exercise of Previously Issued Common Warrants This Prospectus Supplement No. 1 (this “Prospectus Supplement”) supplements the prospectus dated March 21, 2025 (the “Final Prospectus”), relating to the resale

4,253 shares of Common Stock Underlying Previously Issued Common Warrants

Prospectus Supplement No. 1 (To Prospectus dated March 21, 2025) Filed Pursuant to Rule 424(b)(3) Registration Statement No. 333-276511 4,253 shares of Common Stock Underlying Previously Issued Common Warrants This Prospectus Supplement No. 1 (this “Prospectus Supplement”) supplements the prospectus dated March 21, 2025 (the “Final Prospectus”), relating to the offer and sale by us of 4,253 shares

408,640 shares of Common Stock Underlying Previously Issued Common Warrants

Prospectus Supplement No. 1 (To Prospectus dated March 21, 2025) Filed Pursuant to Rule 424(b)(3) Registration Statement No. 333-271049 408,640 shares of Common Stock Underlying Previously Issued Common Warrants This Prospectus Supplement No. 1 (this “Prospectus Supplement”) supplements the prospectus dated March 21, 2025 (the “Final Prospectus”), relating to the offer and sale by us of 408,640 sh

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): August 15, 2025 Commission File N

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): August 15, 2025 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of inc

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended June 30, 2025 ☐TRANSITION REPORT PURSUANT TO SEC

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended June 30, 2025 or ☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File No. 001-14778 SOLIGENIX

Consulting Agreement effective as of August 16, 2025 between Soligenix, Inc. and Richard Straube, MD.*

EXHIBIT 10.1 CONSULTING AGREEMENT This Consulting Agreement (“Agreement”) shall be effective as of August 16, 2025 by and between Richard Straube, M.D., M.Sc. (“Consultant”), having a residential address at 2207 Milford Warren Glen Road, Bloomsbury, NJ 08804, and Soligenix Inc., a Delaware corporation (“Company”). Now, therefore, Consultant and Company agree as follows: 1.Engagement. Company hereb

Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): July 31, 2025 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) delaware 41-1505029 (State or other jurisdiction of incor

Biological Efficacy Demonstrated in a Phase 2 Clinical Trial of SGX945 for the treatment of Behçet’s Disease Study results support advancing SGX945 in this difficult to treat orphan disease

Exhibit 99.1 Biological Efficacy Demonstrated in a Phase 2 Clinical Trial of SGX945 for the treatment of Behçet’s Disease Study results support advancing SGX945 in this difficult to treat orphan disease Princeton, NJ – July 31, 2025 – Soligenix, Inc. (Nasdaq: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare di

Calculation of Filing Fee Table. *

EXHIBIT 107 Calculation of Filing Fee Tables Form S-8 (Form Type) Soligenix, Inc. (Exact Name of Registrant as Specified in its Charter) Table 1 – Newly Registered Securities Proposed Fee Maximum Maximum Amount of Security Security Class Calculation Amount Offering Price Aggregate Registration Type Title Rule Registered(1)(2) per Unit Offering Price Fee Rate Fee Equity Common stock, par value $0.0

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits, Submission of Matters to a Vote of Security Holders

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 20, 2025 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of incor

As filed with the Securities and Exchange Commission on June 20, 2025.

As filed with the Securities and Exchange Commission on June 20, 2025. Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM S-8 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 SOLIGENIX, INC. (Exact name of registrant as specified in its charter) Delaware 41-1505029 (State or other jurisdiction of incorporation or organization) (I.R.S. Employer

Form of Restricted Stock Agreement for 2025 Plan

EXHIBIT 10.3 SOLIGENIX, INC. Restricted Stock Purchase Agreement Granted Under the 2025 Equity Incentive Plan THIS RESTRICTED STOCK PURCHASE AGREEMENT (this “Agreement”) made this day of , 20, between Soligenix Inc., a Delaware corporation (the “Company”), and (the “Holder”). This Agreement is subject to the provisions of the Company’s 2025 Equity Incentive Plan (the “Plan”), a copy of which is fu

Soligenix, Inc. 2025 Equity Incentive Plan

EXHIBIT 10.1 SOLIGENIX, INC. 2025 EQUITY INCENTIVE PLAN ADOPTED BY THE BOARD OF DIRECTORS ON MAY 5, 2025 The purpose of the Soligenix, Inc. 2025 Equity Incentive Plan (the “Plan”) is to advance the interests of Soligenix, Inc. by enhancing its ability to attract and retain employees and other persons who can make significant contributions to the success of the Company through ownership of shares o

Form of Stock Option Agreement for 2025 Plan

EXHIBIT 10.2 NOTICE OF GRANT OF STOCK OPTION Notice is hereby given of the following option grant (the “Option”) to purchase shares of the Common Stock of Soligenix, Inc. (the “Corporation”): Optionee: [NAME] Grant Date: [DATE] Vesting Commencement Date: [DATE] Exercise Price: $[PRICE] per share Number of Option Shares: [NUMBER] shares Expiration Date: [DATE] Type of Option: (check as appropriate)

Fourth Amendment to Employment Agreement dated as of May 5, 2025, between Soligenix, Inc. and Christopher J. Schaber, PhD.

EXHIBIT 10.1 FOURTH AMENDMENT TO EMPLOYMENT AGREEMENT This Fourth Amendment to Employment Agreement (the “Amendment”) is made and entered into as of May 5, 2025 by and between Soligenix, Inc., a Delaware corporation having a place of business at 29 Emmons Drive, Suite B-10, Princeton, NJ 08540 (the “Corporation”), and Christopher J. Schaber, Ph.D. (the “Employee”). RECITALS WHEREAS, the Corporatio

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended March 31, 2025 ☐TRANSITION REPORT PURSUANT TO SE

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended March 31, 2025 or ☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File No. 001-14778 SOLIGENI

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant x Filed by a Party other than the Registrant ¨ Check the appropriate box: ¨ Preliminary Proxy Statement ¨ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ¨ Definitive

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

TABLE OF CONTENTS UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement. ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(

Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): March 25, 2025 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of inco

Second Amended and Restated Bylaws of Soligenix, Inc. effective as of March 25, 2025

EXHIBIT 3.1 SECOND AMENDED AND RESTATED BY-LAWS OF SOLIGENIX, INC. ADOPTED AS OF MARCH 25, 2025 ARTICLE I OFFICES SECTION 1.1. REGISTERED OFFICE. The registered office of Soligenix, Inc. (the “CORPORATION”) shall be in the City of Wilmington, County of New Castle, State of Delaware. SECTION 1.2. OTHER OFFICES. The Corporation may also have offices at such other places both within and without the S

Subsidiaries of the Company. ***

EXHIBIT 21.1 SUBSIDIARIES OF SOLIGENIX, INC. The following represents a list of Soligenix, Inc.’s subsidiaries: Name Ownership State of Incorporation Enteron Pharmaceuticals, Inc. 100.00 % Delaware Orasomal Technologies Inc. 75.30 % Delaware Soligenix BioPharma Canada Incorporated 100.00 % Canada Soligenix UK Limited 100.00 % United Kingdom Soligenix NE B.V. 100.00 % Netherlands Soligenix Biopharm

As filed with the Securities and Exchange Commission on March 21, 2025.

Table of Contents As filed with the Securities and Exchange Commission on March 21, 2025.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the Fiscal Year Ended December 31, 2024 ☐TRANSITION REPORT PURSUAN

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the Fiscal Year Ended December 31, 2024 ☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the transition period from to Commission File No. 001-14778 SOL

Subsidiaries of the Company. ***

EXHIBIT 21.1 SUBSIDIARIES OF SOLIGENIX, INC. The following represents a list of Soligenix, Inc.’s subsidiaries: Name Ownership State of Incorporation Enteron Pharmaceuticals, Inc. 100.00 % Delaware Orasomal Technologies Inc. 75.30 % Delaware Soligenix BioPharma Canada Incorporated 100.00 % Canada Soligenix UK Limited 100.00 % United Kingdom Soligenix NE B.V. 100.00 % Netherlands Soligenix Biopharm

Subsidiaries of the Company. ***

EXHIBIT 21.1 SUBSIDIARIES OF SOLIGENIX, INC. The following represents a list of Soligenix, Inc.’s subsidiaries: Name Ownership State of Incorporation Enteron Pharmaceuticals, Inc. 100.00 % Delaware Orasomal Technologies Inc. 75.30 % Delaware Soligenix BioPharma Canada Incorporated 100.00 % Canada Soligenix UK Limited 100.00 % United Kingdom Soligenix NE B.V. 100.00 % Netherlands Soligenix Biopharm

Description of Securities. *

EXHIBIT 4.1 SOLIGENIX, INC. DESCRIPTION OF SECURITIES The following description of the terms of our securities is not complete and is qualified in its entirety by reference to our Certificate of Incorporation, as amended (the “Certificate of Incorporation”) and our Bylaws, as amended (the “Bylaws”), both of which are filed as exhibits to our Annual Reports on Form 10-K. Under our Certificate of In

Subsidiaries of the Company. *

EXHIBIT 21.1 SUBSIDIARIES OF SOLIGENIX, INC. The following represents a list of Soligenix, Inc.’s subsidiaries: Name Ownership State of Incorporation Enteron Pharmaceuticals, Inc. 100.00 % Delaware Orasomal Technologies Inc. 75.30 % Delaware Soligenix BioPharma Canada Incorporated 100.00 % Canada Soligenix UK Limited 100.00 % United Kingdom Soligenix NE B.V. 100.00 % Netherlands Soligenix Biopharm

As filed with the Securities and Exchange Commission on March 21, 2025.

Table of Contents As filed with the Securities and Exchange Commission on March 21, 2025.

As filed with the Securities and Exchange Commission on March 21, 2025.

As filed with the Securities and Exchange Commission on March 21, 2025. Registration No. 333-271049 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 SOLIGENIX, INC. (Exact Name of Registrant as Specified in Its Charter) Delaware 2834 41-1505029 (State or Other Jurisdiction of I

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): February 5, 2025 Commission File

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): February 5, 2025 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of in

Up to 1,054,688 Shares of Common Stock Issuable Upon the Exercise of Previously Issued Common Warrants

Prospectus Supplement No. 2 (To Prospectus dated July 24, 2024) Filed Pursuant to Rule 424(b)(3) Registration Statement No. 333-280993 Up to 1,054,688 Shares of Common Stock Issuable Upon the Exercise of Previously Issued Common Warrants This Prospectus Supplement No. 2 (this “Prospectus Supplement”) supplements the prospectus dated July 24, 2024 (the “Final Prospectus”), relating to the resale fr

4,253 shares of Common Stock Underlying Previously Issued Common Warrants

Prospectus Supplement No. 3 (To Prospectus dated April 17, 2024) Filed Pursuant to Rule 424(b)(3) Registration Statement No. 333-276511 4,253 shares of Common Stock Underlying Previously Issued Common Warrants This Prospectus Supplement No. 3 (this “Prospectus Supplement”) supplements the prospectus dated April 17, 2024 (the “Final Prospectus”), relating to the offer and sale by us of 4,253 shares

Up to $5,800,000 of shares of Common Stock

Prospectus Supplement No. 2 (To Prospectus dated December 15, 2023) Filed Pursuant to Rule 424(b)(3) Registration Statement No. 333-274265 Up to $5,800,000 of shares of Common Stock This Prospectus Supplement No. 2 (this “Prospectus Supplement”) supplements the prospectus dated December 15, 2023 (the “Final Prospectus”), relating to the offer and sale by us of up to $5,800,000 shares of our common

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended September 30, 2024 ☐TRANSITION REPORT PURSUANT T

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended September 30, 2024 or ☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File No. 001-14778 SOLI

Entry into a Material Definitive Agreement, Financial Statements and Exhibits, Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): October 8, 2024 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of inc

Amendment to Loan and Security Agreement dated as of October 8, 2024 (incorporated by reference to Exhibit 10.1 included in our current report on Form 8-K filed on October 11, 2024).

EXHIBIT 10.1 SECOND AMENDMENT TO THE LOAN AGREEMENT This Second Amendment (the “Second Amendment”) to the Loan and Security Agreement, dated as of December 15, 2020, as amended by the First Amendment dated April 19, 2023 (as amended, the “Agreement”) is made and entered into on October 8, 2024 (the “Effective Date”) by and between Soligenix, Inc., a corporation incorporated in the State of Delawar

At Market Issuance Sales Agreement dated August 16, 2024 between Soligenix, Inc. and A.G.P./Alliance Global Partners (incorporated by reference to Exhibit 10.1 included in our current report on Form 8-K filed on August 16, 2024).

EXHIBIT 10.1 SOLIGENIX, INC. Common Stock (par value $0.001 per share) At Market Issuance Sales Agreement August 16, 2024 A.G.P./Alliance Global Partners 590 Madison Avenue, 28th Floor New York, NY 10022 Ladies and Gentlemen: Soligenix, Inc., a Delaware corporation (the “Company”), confirms its agreement (this “Agreement”) with A.G.P./Alliance Global Partners (“AGP”) as follows: 1. Issuance and Sa

Up to $5,800,000 Soligenix, Inc. COMMON STOCK

Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-274265 PROSPECTUS SUPPLEMENT (To prospectus dated December 15, 2023) Up to $5,800,000 Soligenix, Inc. COMMON STOCK We have entered into an At Market Issuance Sales Agreement (the “sales agreement”) with A.G.P./Alliance Global Partners (“A.G.P.” or the “sales agent”), dated August 16, 2024, relating to shares of our common stoc

Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): August 16, 2024 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of inc

7,042,000 shares of Common Stock Underlying Previously Issued Pre-Funded Warrants 11,875,000 shares of Common Stock Underlying Previously Issued Common Warrants

Prospectus Supplement No. 2 (To Prospectus dated April 17, 2024) Filed Pursuant to Rule 424(b)(3) Registration Statement No. 333-276511 7,042,000 shares of Common Stock Underlying Previously Issued Pre-Funded Warrants 11,875,000 shares of Common Stock Underlying Previously Issued Common Warrants This Prospectus Supplement No. 2 (this “Prospectus Supplement”) supplements the prospectus dated April

Up to 1,054,688 Shares of Common Stock Issuable Upon the Exercise of Previously Issued Common Warrants

Prospectus Supplement No. 1 (To Prospectus dated July 24, 2024) Filed Pursuant to Rule 424(b)(3) Registration Statement No. 333-280993 Up to 1,054,688 Shares of Common Stock Issuable Upon the Exercise of Previously Issued Common Warrants This Prospectus Supplement No. 1 (this “Prospectus Supplement”) supplements the prospectus dated July 24, 2024 (the “Final Prospectus”), relating to the resale fr

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended June 30, 2024 ☐TRANSITION REPORT PURSUANT TO SEC

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended June 30, 2024 or ☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File No. 001-14778 SOLIGENIX

Soligenix, Inc. 29 Emmons Drive, Suite B-10 Princeton, NJ 08540

Soligenix, Inc. 29 Emmons Drive, Suite B-10 Princeton, NJ 08540 July 30, 2024 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, DC 20549 Re: Soligenix, Inc. Registration Statement on Form S-1 File No. 333-280993 Ladies and Gentlemen: Pursuant to Rule 461 under the Securities Act of 1933 and on behalf of Soligenix, Inc. (the “C

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): July 24, 2024 Commission File No.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): July 24, 2024 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of incor

Subsidiaries of the Company. *

Exhibit 21.1 SUBSIDIARIES OF SOLIGENIX, INC. The following represents a list of Soligenix, Inc.’s subsidiaries: Name Ownership State of Incorporation Enteron Pharmaceuticals, Inc. 100.00 % Delaware Orasomal Technologies Inc. 75.30 % Delaware Soligenix BioPharma Canada Incorporated 100.00 % Canada Soligenix UK Limited 100.00 % United Kingdom Soligenix NE B.V. 100.00 % Netherlands Soligenix Biopharm

Filing Fee Table. *

Exhibit 107 Calculation of Filing Fee Table FORM S-1 (Form Type) Soligenix, Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered Securities Security Type Security Class Title Fee Calculation Rate Amount Registered Maximum Aggregate Offering Price (1) Fee Rate Amount of Registration Fee Fees to be Paid Equity Common Stock issuable upon exercise of Common Warrants 45

As filed with the Securities and Exchange Commission on July 24, 2024.

Table of Contents As filed with the Securities and Exchange Commission on July 24, 2024.

Financial Advisory Agreement, dated as of July 9, 2024, between A.G.P./Alliance Global Partners and the Company.

July 9, 2024 CONFIDENTIAL Soligenix, Inc. 29 Emmons Drive, Suite B-10 Princeton, NJ 08540 Attention: Dr. Christopher J. Schaber Ph.D., CEO Re: Soligenix, Inc.– Financial Advisory Agreement Dear Dr. Schaber, The purpose of this letter (this “Agreement”) is to confirm the engagement of A.G.P./Alliance Global Partners (“A.G.P.”) by Soligenix, Inc., a Delaware corporation (the “Company”), to render Fi

Form of Warrant to Purchase Shares of Common Stock issued in connection with July 2024 warrant inducement agreement (incorporated by reference to Exhibit 4.1 included in our current report on Form 8-K filed on July 9, 2024).

EXHIBIT 4.1 NEITHER THIS SECURITY NOR THE SECURITIES INTO WHICH THIS SECURITY IS EXERCISABLE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE REGIST

Form of Warrant Inducement Agreement, by and between the Company and each Holder (incorporated by reference to Exhibit 10.1 included in our current report on Form 8-K filed on July 9, 2024).

EXHIBIT 10.1 SOLIGENIX, INC. 29 Emmons Drive, Suite B-10 Princeton, NJ 08540 July 9, 2024 To the Holder of April 2024 Common Stock Purchase Warrants Re: Inducement Offer to Exercise Existing Common Stock Purchase Warrants Dear Holder: SOLIGENIX, INC. (the “Company”) is pleased to offer (this “Inducement Offer”) to you (“Holder”, “you” or similar terminology) the opportunity to receive new warrants

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): July 9, 2024 Commission File No.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): July 9, 2024 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of incorp

Regulation FD Disclosure, Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year, Material Modification to Rights of Security Holders, Financial Statements and Exhibits, Submission of Matters to a Vote of Security Holders

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 30, 2024 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of incorp

Certificate of Amendment to Second Amended and Restated Certificate of Incorporation of Soligenix, Inc. (incorporated by reference to Exhibit 3.1 included in our current report on Form 8-K filed on May 31, 2024).

EXHIBIT 3.1 CERTIFICATE OF AMENDMENT TO SECOND AMENDED AND RESTATED CERTIFICATE OF INCORPORATION THE UNDERSIGNED, being a duly appointed officer of Soligenix, Inc. (the “Corporation”), a corporation organized and existing under and by virtue of the Delaware General Corporation Law of the State of Delaware (the “DGCL”), for the purpose of amending the Corporation’s Second Amended and Restated Certi

Soligenix Announces Reverse Stock Split Common Stock Will Begin Trading on Split-Adjusted Basis on June 6, 2024

EXHIBIT 99.1 Soligenix Announces Reverse Stock Split Common Stock Will Begin Trading on Split-Adjusted Basis on June 6, 2024 PRINCETON, NJ – May 31, 2024 – Soligenix, Inc. (NASDAQ: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unmet medical need, announced today that it intends to

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement. ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitiv

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement. ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitiv

Soligenix, Inc. Announces Adjournment of Annual Meeting, Information for Reconvened Annual Meeting

EXHIBIT 99.1 Soligenix, Inc. Announces Adjournment of Annual Meeting, Information for Reconvened Annual Meeting Princeton, NJ – May 24, 2024 – Soligenix, Inc. (Nasdaq: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unmet medical need, announced today that its 2024 Annual Meeting of

Regulation FD Disclosure, Financial Statements and Exhibits, Submission of Matters to a Vote of Security Holders

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 23, 2024 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of incorp

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement. ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitiv

Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 17, 2024 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of incorp

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement. ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitiv

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement. ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitiv

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended March 31, 2024 ☐TRANSITION REPORT PURSUANT TO SE

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended March 31, 2024 or ☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File No. 001-14778 SOLIGENI

7,042,000 shares of Common Stock Underlying Previously Issued Pre-Funded Warrants 11,875,000 shares of Common Stock Underlying Previously Issued Common Warrants

Prospectus Supplement (To Prospectus dated April 17, 2024) Filed Pursuant to Rule 424(b)(3) Registration Statement No.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

TABLE OF CONTENTS UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement. ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(

Soligenix Announces Pricing of $4.75 Million Public Offering

EXHIBIT 99.1 Soligenix Announces Pricing of $4.75 Million Public Offering PRINCETON, N.J., April 18, 2024 Soligenix, Inc. (Nasdaq: SNGX) (“Soligenix” or the “Company”), a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unmet medical need, today announced the pricing of its public offering of 11,875,000 shares of commo

Form of Pre-Funded Warrant issued in April 2024 public offering (incorporated by reference to Exhibit 4.1 included in our current report on Form 8-K filed on April 22, 2024).

EXHIBIT 4.1 PRE-FUNDED WARRANT TO PURCHASE SHARES OF COMMON STOCK SOLIGENIX, INC. Warrant Shares: Original Issuance Date: April 22, 2024 THIS PRE-FUNDED WARRANT TO PURCHASE SHARES OF COMMON STOCK (this “Warrant”) certifies that, for value received, or its assigns (the “Holder”) is entitled, upon the terms and subject to the limitations on exercise and the conditions hereinafter set forth, at any t

Placement Agency Agreement dated April 17, 2024.

EXHIBIT 10.1 A.G.P./Alliance Global Partners 590 Madison Avenue, 28th Floor New York, NY 10022 April 17, 2024 Soligenix, Inc. Attention: Christopher J. Schaber, President and Chief Executive Officer 29 Emmons Drive, Suite B-10 Princeton, NJ 08540 Re: Placement Agency Agreement Dear Dr. Schaber: Subject to the terms and conditions of this letter agreement (the “Agreement”) between A.G.P./Alliance G

Securities Purchase Agreement dated April 17, 2024 (incorporated by reference to Exhibit 10.2 included in our current report on Form 8-K filed on April 22, 2024).

EXHIBIT 10.2 SECURITIES PURCHASE AGREEMENT This Securities Purchase Agreement (this “Agreement”) is dated as of April 17, 2024, between Soligenix, Inc., a Delaware corporation (the “Company”), and each purchaser identified on the signature pages hereto (each, including its successors and assigns, a “Purchaser” and collectively the “Purchasers”). WHEREAS, subject to the terms and conditions set for

Form of Common Warrant issued in April 2024 public offering (incorporated by reference to Exhibit 4.2 included in our current report on Form 8-K filed on April 22, 2024).

EXHIBIT 4.2 WARRANT TO PURCHASE SHARES OF COMMON STOCK SOLIGENIX, INC. Warrant Shares: Original Issuance Date: April 22, 2024 THIS WARRANT TO PURCHASE SHARES OF COMMON STOCK (this “Warrant”) certifies that, for value received, or its assigns (the “Holder”) is entitled, upon the terms and subject to the limitations on exercise and the conditions hereinafter set forth, at any time on or after the da

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): April 17, 2024 Commission File No

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): April 17, 2024 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of inco

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

TABLE OF CONTENTS UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☒ Preliminary Proxy Statement. ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(

3,275,000 Shares of Common Stock Pre-Funded Warrants to Purchase 8,600,000 Shares of Common Stock Common Warrants to Purchase 11,875,000 Shares of Common Stock 8,600,000 shares of Common Stock Underlying the Pre-Funded Warrants 11,875,000 shares of C

Prospectus Filed Pursuant to Rule 424(b)(4) Registration Statement No. 333-276511 3,275,000 Shares of Common Stock Pre-Funded Warrants to Purchase 8,600,000 Shares of Common Stock Common Warrants to Purchase 11,875,000 Shares of Common Stock 8,600,000 shares of Common Stock Underlying the Pre-Funded Warrants 11,875,000 shares of Common Stock Underlying the Common Warrants We are offering 3,275,000

Soligenix, Inc. 29 Emmons Drive, Suite B-10 Princeton, NJ 08540

Soligenix, Inc. 29 Emmons Drive, Suite B-10 Princeton, NJ 08540 April 15, 2024 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, DC 20549 Re: Soligenix, Inc. Registration Statement on Form S-1 File No. 333-276511 Ladies and Gentlemen: Pursuant to Rule 461 under the Securities Act of 1933 and on behalf of Soligenix, Inc. (the “

A.G.P. / Alliance Global Partners 590 Madison Ave., 28th Floor New York, NY 10022 April 15, 2024

CORRESP 1 filename1.htm A.G.P. / Alliance Global Partners 590 Madison Ave., 28th Floor New York, NY 10022 April 15, 2024 VIA EDGAR U.S. Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, D.C. 20549 Re: Soligenix, Inc. Registration Statement on Form S-1, as amended File No: 333-276511 Ladies and Gentlemen: Pursuant to Rule 461 promulgated under the Sec

Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): April 3, 2024 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of incor

Soligenix Announces Agreement on the Design of a Second Confirmatory Placebo-Controlled Trial for HyBryte™ With the European Medicines Agency Randomized Study with 18 Weeks Continuous Treatment Expected to Replicate and Extend Results from the First,

EXHIBIT 99.1 Soligenix Announces Agreement on the Design of a Second Confirmatory Placebo-Controlled Trial for HyBryte™ With the European Medicines Agency Randomized Study with 18 Weeks Continuous Treatment Expected to Replicate and Extend Results from the First, Statistically Significant Phase 3 Study Princeton, NJ – April 3, 2024 – Soligenix, Inc. (Nasdaq: SNGX) (Soligenix or the Company), a lat

Soligenix, Inc. 29 Emmons Drive, Suite B-10 Princeton, NJ 08540

Soligenix, Inc. 29 Emmons Drive, Suite B-10 Princeton, NJ 08540 April 3, 2024 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, DC 20549 Re: Soligenix, Inc. Withdrawal of Request for Acceleration of Effectiveness of Registration Statement Registration Statement on Form S-1, as amended Commission File No. 333-276511 Ladies and

Forward-Looking Statements This presentation contains forward-looking statements. All statements other than statements of historical facts contained in this presentation, including statements regarding our future results of operations and financial p

Exhibit 99.2 Rising to the Challenges of Rare Disease Treatment NASDAQ: SNGX April 03, 2024 Forward-Looking Statements This presentation contains forward-looking statements. All statements other than statements of historical facts contained in this presentation, including statements regarding our future results of operations and financial position, business strategy, prospective products and produ

Soligenix, Inc. 29 Emmons Drive, Suite B-10 Princeton, NJ 08540

Soligenix, Inc. 29 Emmons Drive, Suite B-10 Princeton, NJ 08540 April 2, 2024 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, DC 20549 Re: Soligenix, Inc. Registration Statement on Form S-1 File No. 333-276511 Ladies and Gentlemen: Pursuant to Rule 461 under the Securities Act of 1933 and on behalf of Soligenix, Inc. (the “C

A.G.P. / Alliance Global Partners 590 Madison Ave., 28th Floor New York, NY 10022 April 2, 2024

A.G.P. / Alliance Global Partners 590 Madison Ave., 28th Floor New York, NY 10022 April 2, 2024 VIA EDGAR U.S. Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, D.C. 20549 Re: Soligenix, Inc. Registration Statement on Form S-1, as amended File No: 333-276511 Ladies and Gentlemen: Pursuant to Rule 461 promulgated under the Securities Act of 1933, as a

As filed with the Securities and Exchange Commission on April 2, 2024.

Table of Contents As filed with the Securities and Exchange Commission on April 2, 2024.

Incentive Compensation Recoupment Policy. *

Exhibit 97 SOLIGENIX, INC. INCENTIVE COMPENSATION RECOUPMENT POLICY 1. Introduction. The Board of Directors (the “Board”) of Soligenix, Inc. (the “Company”) believes that it is in the best interests of the Company and its shareholders to create and maintain a culture that emphasizes integrity and accountability and that reinforces the Company’s pay-for-performance compensation philosophy. The Boar

As filed with the Securities and Exchange Commission on March 15, 2024.

Table of Contents As filed with the Securities and Exchange Commission on March 15, 2024.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the Fiscal Year Ended December 31, 2023 ☐TRANSITION REPORT PURSUAN

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the Fiscal Year Ended December 31, 2023 ☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the transition period from to Commission File No. 001-14778 SOL

Insider Trading Policy. *

Exhibit 19.1 ADMINISTRATIVE POLICY INSIDER TRADING ADM 1100 REVISION DATE: May 18, 2021 I. PURPOSE The following is the insider trading policy of Soligenix, Inc. and Subsidiaries (the "Company") and outlines the procedures that all Company personnel must follow. This policy and these procedures arise from the Company’s responsibilities as a publicly-traded entity. Failure to comply with these proc

Subsidiaries of the Company. *

EXHIBIT 21.1 SUBSIDIARIES OF SOLIGENIX, INC. The following represents a list of Soligenix, Inc.’s subsidiaries: Name Ownership State of Incorporation Enteron Pharmaceuticals, Inc. 100.00 % Delaware Orasomal Technologies Inc. 75.30 % Delaware Soligenix BioPharma Canada Incorporated 100.00 % Canada Soligenix UK Limited 100.00 % United Kingdom Soligenix NE B.V. 100.00 % Netherlands Soligenix Biopharm

Description of Securities. *

EXHIBIT 4.1 SOLIGENIX, INC. DESCRIPTION OF SECURITIES The following description of the terms of our securities is not complete and is qualified in its entirety by reference to our Certificate of Incorporation, as amended (the “Certificate of Incorporation”) and our Bylaws, as amended (the “Bylaws”), both of which are filed as exhibits to our Annual Reports on Form 10-K. Under our Certificate of In

Form of Common Warrant. *

EXHIBIT 4.2 WARRANT TO PURCHASE SHARES OF COMMON STOCK SOLIGENIX, INC. Warrant Shares: Original Issuance Date: [•], 2024 THIS WARRANT TO PURCHASE SHARES OF COMMON STOCK (this “Warrant”) certifies that, for value received, or its assigns (the “Holder”) is entitled, upon the terms and subject to the limitations on exercise and the conditions hereinafter set forth, at any time on or after the date he

Filing Fee Table. *

Exhibit 107 Calculation of Filing Fee Table FORM S-1 (Form Type) Soligenix, Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered Securities Security Type Security Class Title Fee Calculation Rate Amount Registered Proposed Maximum Offering Price Per Unit Maximum Aggregate Offering Price (1) Fee Rate Amount of Registration Fee Fees to be paid Equity Common Stock (2)

Form of Securities Purchase Agreement. *

EXHIBIT 4.4 SECURITIES PURCHASE AGREEMENT This Securities Purchase Agreement (this “Agreement”) is dated as of [·], 2024, between Soligenix, Inc., a Delaware corporation (the “Company”), and each purchaser identified on the signature pages hereto (each, including its successors and assigns, a “Purchaser” and collectively the “Purchasers”). WHEREAS, subject to the terms and conditions set forth in

Form of Pre-Funded Warrant. *

EXHIBIT 4.3 PRE-FUNDED WARRANT TO PURCHASE SHARES OF COMMON STOCK SOLIGENIX, INC. Warrant Shares: Original Issuance Date: [•], 2024 THIS PRE-FUNDED WARRANT TO PURCHASE SHARES OF COMMON STOCK (this “Warrant”) certifies that, for value received, or its assigns (the “Holder”) is entitled, upon the terms and subject to the limitations on exercise and the conditions hereinafter set forth, at any time o

Form of Placement Agent Agreement. *

EXHIBIT 1.1 A.G.P./Alliance Global Partners 590 Madison Avenue, 28th Floor New York, NY 10022 [•], 2024 Soligenix, Inc. Attention: Christopher J. Schaber, President and Chief Executive Officer 29 Emmons Drive, Suite B-10 Princeton, NJ 08540 Re: Placement Agency Agreement Dear Dr. Schaber: Subject to the terms and conditions of this letter agreement (the “Agreement”) between A.G.P./Alliance Global

Subsidiaries of the Company. *

EXHIBIT 21.1 SUBSIDIARIES OF SOLIGENIX, INC. The following represents a list of Soligenix, Inc.’s subsidiaries: Name Ownership State of Incorporation Enteron Pharmaceuticals, Inc. 100.00 % Delaware Orasomal Technologies Inc. 75.30 % Delaware Soligenix BioPharma Canada Incorporated 100.00 % Canada Soligenix UK Limited 100.00 % United Kingdom Soligenix NE B.V. 100.00 % Netherlands Soligenix Biopharm

As filed with the Securities and Exchange Commission on January 12, 2024.

As filed with the Securities and Exchange Commission on January 12, 2024. Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 SOLIGENIX, INC. (Exact Name of Registrant as Specified in Its Charter) Delaware 2834 41-1505029 (State or Other Jurisdiction of Incorporation or Organization) (Primary

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): December 21, 2023 Commission File

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): December 21, 2023 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of i

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): December 15, 2023 Commission File

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): December 15, 2023 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of i

Soligenix, Inc. 29 Emmons Drive, Suite B-10 Princeton, NJ 08540

Soligenix, Inc. 29 Emmons Drive, Suite B-10 Princeton, NJ 08540 December 14, 2023 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, DC 20549 Re: Soligenix, Inc. Registration Statement on Form S-3 Commission File No. 333-274265 Ladies and Gentlemen: Pursuant to Rule 461 under the Securities Act of 1933 and on behalf of Soligeni

As filed with the Securities and Exchange Commission on December 8, 2023

As filed with the Securities and Exchange Commission on December 8, 2023 Registration No.

Soligenix, Inc. 29 Emmons Drive, Suite B-10 Princeton, NJ 08540

Soligenix, Inc. 29 Emmons Drive, Suite B-10 Princeton, NJ 08540 December 6, 2023 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, DC 20549 Re: Soligenix, Inc. Registration Statement on Form S-3 Commission File No. 333-274265 Ladies and Gentlemen: Reference is made to our letter, filed as correspondence via EDGAR on November 3

Soligenix, Inc. 29 Emmons Drive, Suite B-10 Princeton, NJ 08540

Soligenix, Inc. 29 Emmons Drive, Suite B-10 Princeton, NJ 08540 November 30, 2023 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, DC 20549 333-271049 Re: Soligenix, Inc. Registration Statement on Form S-3 File No. 333-274265 Ladies and Gentlemen: Pursuant to Rule 461 under the Securities Act of 1933 and on behalf of Soligeni

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): November 16, 2023 Commission File

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): November 16, 2023 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of i

Soligenix, Inc. Announces Adjournment of Annual Meeting, Information for Reconvened Annual Meeting

EXHIBIT 99.1 Soligenix, Inc. Announces Adjournment of Annual Meeting, Information for Reconvened Annual Meeting Princeton, NJ – November 17, 2023 – Soligenix, Inc. (Nasdaq: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unmet medical need, announced today that its 2023 Annual Meeti

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended September 30, 2023 ☐TRANSITION REPORT PURSUANT T

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended September 30, 2023 or ☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File No. 001-14778 SOLI

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): October 18, 2023 Commission File

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): October 18, 2023 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of in

Soligenix, Inc. Announces Adjournment of Annual Meeting, Information for Reconvened Annual Meeting

EXHIBIT 99.1 Soligenix, Inc. Announces Adjournment of Annual Meeting, Information for Reconvened Annual Meeting Princeton, NJ – October 20, 2023 – Soligenix, Inc. (Nasdaq: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unmet medical need, announced today that its 2023 Annual Meetin

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement. ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitiv

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement. ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitiv

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement. ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitiv

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement. ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitiv

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement. ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitiv

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement. ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitiv

Soligenix, Inc. Announces Adjournment of Annual Meeting, Information for Reconvened Annual Meeting and Additional Proposal to be Considered by Stockholders

EXHIBIT 99.1 Soligenix, Inc. Announces Adjournment of Annual Meeting, Information for Reconvened Annual Meeting and Additional Proposal to be Considered by Stockholders Princeton, NJ – September 22, 2023 – Soligenix, Inc. (Nasdaq: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unme

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): September 21, 2023 Commission Fil

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): September 21, 2023 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement. ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitiv

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement. ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitiv

Letter from EisnerAmper LLP dated September 15, 2023

EXHIBIT 16.1 September 15, 2023 Securities and Exchange Commission 100 F Street, N.E. Washington, DC 20549 Ladies and Gentlemen: We have read Item 4.01 of Form 8-K dated September 15, 2023 of Soligenix, Inc. and are in agreement with the statements contained therein as it regards our firm. We have no basis to agree or disagree with other statements of the registrant contained in Item 4.01. Sincere

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): September 15, 2023 Commission Fil

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): September 15, 2023 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of

Calculation of Filing Fee Table. **

Exhibit 107 Calculation of Filing Fee Tables Form S-3 (Form Type) Soligenix, Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered and Carry Forward Securities Security Type Security Class Title Fee Calculation or Carry Forward Rule Amount Registered(2) Proposed Maximum Offering Price Per Share(2) Maximum Aggregate Offering Price Fee Rate Amount of Registration Fee

As filed with the Securities and Exchange Commission on August 30, 2023

Table of Contents As filed with the Securities and Exchange Commission on August 30, 2023 Registration No.

Description of Securities. **

EXHIBIT 4.7 SOLIGENIX, INC. DESCRIPTION OF SECURITIES The following description of the terms of our securities is not complete and is qualified in its entirety by reference to our Certificate of Incorporation, as amended (the “Certificate of Incorporation”) and our Bylaws, as amended (the “Bylaws”), both of which are filed as exhibits to our Annual Reports on Form 10-K. Under our Certificate of In

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended June 30, 2023 ☐TRANSITION REPORT PURSUANT TO SEC

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended June 30, 2023 or ☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File No. 001-14778 SOLIGENIX

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 12b-25 NOTIFICATION OF LATE FILING

SEC FILE NUMBER: 001-14778 CUSIP NUMBER: 834223 505 UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 12b-25 NOTIFICATION OF LATE FILING (Check One): ¨ Form 10-K ¨ Form 20-F ¨ Form 11-K x Form 10-Q ¨ Form 10-D ¨ Form N-CEN ¨ Form N-CSR For Period Ended: June 30, 2023 ¨ Transition Report on Form 10-K ¨ Transition Report on Form 20-F ¨ Transition Report on Form 11-K ¨ Transition Report on Form 10-Q For the Transition Period Ended: Nothing in the form shall be construed to imply that the Commission has verified any information contained herein.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant x Filed by a Party other than the Registrant ¨ Check the appropriate box: ¨ Preliminary Proxy Statement. ¨ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ¨ Definitiv

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

TABLE OF CONTENTS UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement. ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): July 7, 2023 Commission File No.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): July 7, 2023 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of incorp

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 23, 2023 Commission File No.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 23, 2023 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of incor

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 23, 2023 Commission File No.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 23, 2023 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of incorp

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended March 31, 2023 ☐TRANSITION REPORT PURSUANT TO SE

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended March 31, 2023 or ☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File No. 001-14778 SOLIGENI

Soligenix Announces Closing of $8.5 Million Public Offering

EXHIBIT 99.2 Soligenix Announces Closing of $8.5 Million Public Offering Princeton, NJ, May 9, 2023 – Soligenix, Inc. (Nasdaq: SNGX) (“Soligenix” or the “Company”), a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unmet medical need, announced today the closing of its previously announced public offering of 6,538,500

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 5, 2023 Commission File No. 0

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 5, 2023 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of incorpo

Soligenix Announces Pricing of $8.5 Million Public Offering

EXHIBIT 99.1 Soligenix Announces Pricing of $8.5 Million Public Offering Princeton, NJ, May 5, 2023 – Soligenix, Inc. (Nasdaq: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unmet medical need, today announced the pricing of its public offering of 6,538,500 shares of common stock (

2,301,500 Shares of Common Stock Pre-Funded Warrants to Purchase 4,237,000 Shares of Common Stock Common Warrants to Purchase 6,538,500 Shares of Common Stock 4,237,000 shares of Common Stock Underlying the Pre-Funded Warrants 6,538,500 shares of Com

Table of Contents Filed Pursuant to Rule 424(b)(4) Registration Statement No. 333-271049 Prospectus 2,301,500 Shares of Common Stock Pre-Funded Warrants to Purchase 4,237,000 Shares of Common Stock Common Warrants to Purchase 6,538,500 Shares of Common Stock 4,237,000 shares of Common Stock Underlying the Pre-Funded Warrants 6,538,500 shares of Common Stock Underlying the Common Warrants We are of

Soligenix, Inc. 29 Emmons Drive, Suite B-10 Princeton, NJ 08540

Soligenix, Inc. 29 Emmons Drive, Suite B-10 Princeton, NJ 08540 May 4, 2023 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, DC 20549 Re: Soligenix, Inc. Registration Statement on Form S-1 File No. 333-271049 Ladies and Gentlemen: Pursuant to Rule 461 under the Securities Act of 1933 and on behalf of Soligenix, Inc. (the “Com

As filed with the Securities and Exchange Commission on May 4, 2023.

Table of Contents As filed with the Securities and Exchange Commission on May 4, 2023.

Soligenix Announces Appointment of Timothy R. Coté, M.D. to its Board of Directors Strengthens regulatory and orphan drug development expertise

EXHIBIT 99.1 Soligenix Announces Appointment of Timothy R. Coté, M.D. to its Board of Directors Strengthens regulatory and orphan drug development expertise Princeton, NJ – May 3, 2023 – Soligenix, Inc. (Nasdaq: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unmet medical need, ann

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 3, 2023 Commission File No. 0

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 3, 2023 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of incorpo

Soligenix Enters into Exclusive Option Agreement with Silk Road Therapeutics for Rights to Topical Pentoxifylline Designed to Treat Behçet’s Disease Phase 2/3-Ready Orphan Disease Program Complements Company’s Existing Late-Stage Rare Disease Pipelin

EXHIBIT 99.1 Soligenix Enters into Exclusive Option Agreement with Silk Road Therapeutics for Rights to Topical Pentoxifylline Designed to Treat Behçet’s Disease Phase 2/3-Ready Orphan Disease Program Complements Company’s Existing Late-Stage Rare Disease Pipeline PRINCETON, NJ – May 1, 2023 – Soligenix, Inc. (Nasdaq: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 1, 2023 Commission File No. 0

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 1, 2023 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of incorpo

Form of Common Warrant. *

Exhibit 4.2 WARRANT TO PURCHASE SHARES OF COMMON STOCK SOLIGENIX, INC. Warrant Shares: Original Issuance Date: April [•], 2023 THIS WARRANT TO PURCHASE SHARES OF COMMON STOCK (this “Warrant”) certifies that, for value received, or its assigns (the “Holder”) is entitled, upon the terms and subject to the limitations on exercise and the conditions hereinafter set forth, at any time on or after the d

Form of Placement Agent Agreement. *

Exhibit 1.1 A.G.P./Alliance Global Partners 590 Madison Avenue, 28th Floor New York, NY 10022 April [•], 2023 Soligenix, Inc. Attention: Christopher J. Schaber, President and Chief Executive Officer 29 Emmons Drive, Suite B-10 Princeton, NJ 08540 Re: Placement Agent Agreement Dear Dr. Schaber: Subject to the terms and conditions of this letter agreement (the “Agreement”) between A.G.P./Alliance Gl

Form of Common Warrant (incorporated by reference to Exhibit 4.3 to the Company’s Registration Statement on Form S-1/A (File No. 333-271049) filed on April 20, 2023).

Exhibit 4.3 PRE-FUNDED WARRANT TO PURCHASE SHARES OF COMMON STOCK SOLIGENIX, INC. Warrant Shares: Original Issuance Date: April [•], 2023 THIS PRE-FUNDED WARRANT TO PURCHASE SHARES OF COMMON STOCK (this “Warrant”) certifies that, for value received, or its assigns (the “Holder”) is entitled, upon the terms and subject to the limitations on exercise and the conditions hereinafter set forth, at any

Form of Securities Purchase Agreement. *

Exhibit 4.4 SECURITIES PURCHASE AGREEMENT This Securities Purchase Agreement (this “Agreement”) is dated as of April [•], 2023, between Soligenix, Inc., a Delaware corporation (the “Company”), and each purchaser identified on the signature pages hereto (each, including its successors and assigns, a “Purchaser” and collectively the “Purchasers”). WHEREAS, subject to the terms and conditions set for

As filed with the Securities and Exchange Commission on April 19, 2023.

Table of Contents As filed with the Securities and Exchange Commission on April 19, 2023.

NEW YORK WASHINGTON, DC SAN FRANCISCO SILICON VALLEY SAN DIEGO LOS ANGELES FORT WORTH

NEW YORK LONDON SINGAPORE PHILADELPHIA CHICAGO WASHINGTON, DC SAN FRANCISCO SILICON VALLEY SAN DIEGO LOS ANGELES BOSTON HOUSTON DALLAS FORT WORTH AUSTIN FIRM and AFFILIATE OFFICES HANOI HO CHI MINH CITY SHANGHAI ATLANTA BALTIMORE WILMINGTON MIAMI BOCA RATON PITTSBURGH NEWARK LAS VEGAS CHERRY HILL LAKE TAHOE MYANMAR ALLIANCES IN MEXICO www.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): April 19, 2023 Commission File No

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): April 19, 2023 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of inco

First Amendment to Loan and Security Agreement, dated April 19, 2023 (incorporated by reference to Exhibit 10.1 included in our current report on Form 8-K filed on April 19, 2023).

EXHIBIT 10.1 FIRST AMENDMENT TO THE LOAN AGREEMENT This First Amendment (the “First Amendment”) to the Loan and Security Agreement, dated as of April 19, 2023 (the “Agreement”), by and between Soligenix, Inc., a corporation incorporated in the State of Delaware, and each of its Subsidiaries from time to time party hereto, including the Subsidiaries set forth on Schedule I to the Agreement (collect

Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): April 14, 2023 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of inco

Soligenix Provides Regulatory Update on HyBryte™

EXHIBIT 99.1 Soligenix Provides Regulatory Update on HyBryte™ Princeton, NJ – April 14, 2023 – Soligenix, Inc. (Nasdaq: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unmet medical need, announced today that the Company convened a Type A Meeting with the United States (U.S.) Food a

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): April 6, 2023 Commission File No.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): April 6, 2023 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of incor

Subsidiaries of the Company. *

EXHIBIT 21.1 SUBSIDIARIES OF SOLIGENIX, INC. The following represents a list of Soligenix, Inc.’s subsidiaries: Name Ownership State of Incorporation Enteron Pharmaceuticals, Inc. 100.00 % Delaware Orasomal Technologies Inc. 75.30 % Delaware Soligenix BioPharma Canada Incorporated 100.00 % Canada Soligenix UK Limited 100.00 % United Kingdom Soligenix NE B.V. 100.00 % Netherlands Soligenix Biopharm

Power of Attorney. *

S-1 1 tmb-20230331xs1.htm S-1 Table of Contents As filed with the Securities and Exchange Commission on March 31, 2023. Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 SOLIGENIX, INC. (Exact Name of Registrant as Specified in Its Charter) Delaware 2834 41-1505029 (State or Other Jurisdict

Filing Fee Table. *

Exhibit 107 Calculation of Filing Fee Table FORM S-1 (Form Type) Soligenix, Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered Securities Security Type Security Class Title Fee Calculation Rate Amount Registered Proposed Maximum Offering Price Per Unit Maximum Aggregate Offering Price (1) Fee Rate Amount of Registration Fee Fees to be paid Equity Common Stock (2)

Subsidiaries of the Company. *

EXHIBIT 21.1 SUBSIDIARIES OF SOLIGENIX, INC. The following represents a list of Soligenix, Inc.’s subsidiaries: Name Ownership State of Incorporation Enteron Pharmaceuticals, Inc. 100.00 % Delaware Orasomal Technologies Inc. 75.30 % Delaware Soligenix BioPharma Canada Incorporated 100.00 % Canada Soligenix UK Limited 100.00 % United Kingdom Soligenix NE B.V. 100.00 % Netherlands Soligenix Biopharm

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the Fiscal Year Ended December 31, 2022 ☐TRANSITION REPORT PURSUAN

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the Fiscal Year Ended December 31, 2022 ☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the transition period from to Commission File No. 001-14778 SOL

Exhibit 4.1

EX-4.1 2 sngx-20221231xex4d1.htm EX-4.1 EXHIBIT 4.1 SOLIGENIX, INC. DESCRIPTION OF SECURITIES The following description of the terms of our securities is not complete and is qualified in its entirety by reference to our Certificate of Incorporation, as amended (the “Certificate of Incorporation”) and our Bylaws, as amended (the “Bylaws”), both of which are filed as exhibits to our Annual Reports o

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): February 21, 2023 Commission File

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): February 21, 2023 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of i

Soligenix Receives Refusal to File Letter from U.S. FDA for HyBryte™ New Drug Application in the Treatment of Cutaneous T-Cell Lymphoma Soligenix intends to seek guidance from the FDA on how to further advance HyBryte™ towards potential approval

EXHIBIT 99.1 Soligenix Receives Refusal to File Letter from U.S. FDA for HyBryte™ New Drug Application in the Treatment of Cutaneous T-Cell Lymphoma Soligenix intends to seek guidance from the FDA on how to further advance HyBryte™ towards potential approval Princeton, NJ – February 14, 2023 – Soligenix, Inc. (Nasdaq: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): February 14, 2023 Commission File

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): February 14, 2023 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of i

Soligenix Announces Reverse Stock Split Common Stock Will Begin Trading on Split-Adjusted Basis on February 10, 2023

EXHIBIT 99.1 Soligenix Announces Reverse Stock Split Common Stock Will Begin Trading on Split-Adjusted Basis on February 10, 2023 PRINCETON, N.J., February 9, 2023 /PRNewswire/ – Soligenix, Inc. (NASDAQ: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unmet medical need, today annou

Certificate of Amendment to Second Amended and Restated Certificate of Incorporation of Soligenix, Inc. (incorporated by reference to Exhibit 3.1 included in our current report on Form 8-K filed on February 9, 2023).

EXHIBIT 3.1 CERTIFICATE OF AMENDMENT TO SECOND AMENDED AND RESTATED CERTIFICATE OF INCORPORATION THE UNDERSIGNED, being a duly appointed officer of Soligenix, Inc. (the “Corporation”), a corporation organized and existing under and by virtue of the Delaware General Corporation Law of the State of Delaware (the “DGCL”), for the purpose of amending the Corporation’s Second Amended and Restated Certi

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): February 8, 2023 Commission File

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): February 8, 2023 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of in

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement. ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitiv

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): January 11, 2023 Commission File

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): January 11, 2023 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of in

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

? ? ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 ? Filed by the Registrant ? Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement. ? ? ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): December 21, 2022 Commission File

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): December 21, 2022 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of i

Certificate of Designation of the Series D Preferred Stock of the Company dated December 27, 2022 (incorporated by reference to Exhibit 3.1 to our registration statement on Form 8-A filed on December 27, 2022).

EXHIBIT 3.1 SOLIGENIX, INC. CERTIFICATE OF DESIGNATION OF SERIES D PREFERRED STOCK Pursuant to Section 151 of the General Corporation Law of the State of Delaware The undersigned does hereby certify, on behalf of Soligenix, Inc., a Delaware corporation (the “Corporation”), that the following resolution was duly adopted by the board of directors of the Corporation (the “Board of Directors”), in acc

Certificate of Designation of the Series D Preferred Stock of the Company dated December 27, 2022 (incorporated by reference to Exhibit 3.1 to our registration statement on Form 8-A filed on December 27, 2022).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-A FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES PURSUANT TO SECTION 12(b) OR 12(g) OF THE SECURITIES EXCHANGE ACT OF 1934 Soligenix, Inc. (Exact name of registrant as specified in its charter) Delaware 41-1505029 (State or other jurisdiction of incorporation or organization) (IRS Employer Identification No.) 29 Emmo

Soligenix Announces Distribution of Series D Preferred Stock to Holders of its Common Stock

EX-99.1 2 tmb-20221221xex99d1.htm EX-99.1 EXHIBIT 99.1 Soligenix Announces Distribution of Series D Preferred Stock to Holders of its Common Stock Princeton, NJ – December 23, 2022 – Soligenix, Inc. (Nasdaq: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unmet medical need, announc

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): December 20, 2022 Commission File

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): December 20, 2022 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of i

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

? ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 ? Filed by the Registrant ? Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement. ? ? ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ?

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): December 19, 2022 Commission File

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): December 19, 2022 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of i

Soligenix Initiates Phase 2 Clinical Trial of SGX302 (synthetic hypericin) for the Treatment of Mild-to-Moderate Psoriasis Study HPN-PSR-01 opens patient enrollment

EXHIBIT 99.1 Soligenix Initiates Phase 2 Clinical Trial of SGX302 (synthetic hypericin) for the Treatment of Mild-to-Moderate Psoriasis Study HPN-PSR-01 opens patient enrollment PRINCETON, NJ – December 19, 2022 – Soligenix, Inc. (Nasdaq: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is

Soligenix Announces Submission of New Drug Application to the FDA for HyBryte™ in the Treatment of Cutaneous T-cell Lymphoma

EXHIBIT 99.1 Soligenix Announces Submission of New Drug Application to the FDA for HyBryte™ in the Treatment of Cutaneous T-cell Lymphoma Princeton, NJ – December 15, 2022 – Soligenix, Inc. (Nasdaq: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unmet medical need, announced today

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): December 15, 2022 Commission File

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): December 15, 2022 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of i

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): November 16, 2022 Commission File

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): November 16, 2022 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of i

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 ? Filed by the Registrant ? Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement. ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ? Defin

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 ? Filed by the Registrant ? Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement. ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ? Defin

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 ? Filed by the Registrant ? Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement. ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ? Defin

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended September 30, 2022 ☐TRANSITION REPORT PURSUANT T

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended September 30, 2022 or ☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File No. 001-14778 SOLI

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 ? Filed by the Registrant ? Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement. ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ? Defin

Calculation of Filing Fee Table. *

EXHIBIT 107 Calculation of Filing Fee Tables Form S-8 (Form Type) Soligenix, Inc. (Exact Name of Registrant as Specified in its Charter) Table 1 – Newly Registered Securities Security Type Security Class Title Fee Calculation Rule Amount Registered(1)(2) Proposed Maximum Offering Price per Unit Maximum Aggregate Offering Price Fee Rate Amount of Registration Fee Equity Common stock, par value $0.0

As filed with the Securities and Exchange Commission on October 28, 2022.

As filed with the Securities and Exchange Commission on October 28, 2022. Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM S-8 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 SOLIGENIX, INC. (Exact name of registrant as specified in its charter) Delaware 41-1505029 (State or other jurisdiction of incorporation or organization) (I.R.S. Emplo

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): October 27, 2022 Commission File

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): October 27, 2022 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of in

Soligenix Invited to Submit BARDA Contract Proposal for Development of Thermostabilized Subunit Vaccines for Sudan Ebola and Marburg Viruses

EXHIBIT 99.1 Soligenix Invited to Submit BARDA Contract Proposal for Development of Thermostabilized Subunit Vaccines for Sudan Ebola and Marburg Viruses ● Emerging infectious diseases where no protective vaccines are currently available ● SuVax™ targets Sudan ebolavirus, origin of a current disease outbreak in Uganda Princeton, NJ – October 27, 2022 – Soligenix, Inc. (Nasdaq: SNGX) (Soligenix or

Soligenix Announces Formation of Psoriasis Medical Advisory Board Phase 2a clinical study in mild-to-moderate psoriasis initiating in December 2022

EXHIBIT 99.1 Soligenix Announces Formation of Psoriasis Medical Advisory Board Phase 2a clinical study in mild-to-moderate psoriasis initiating in December 2022 Princeton, NJ – October 25, 2022 – Soligenix, Inc. (Nasdaq: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unmet medical

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): October 25, 2022 Commission File

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): October 25, 2022 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of in

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): October 19, 2022 Commission File

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): October 19, 2022 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of in

Soligenix Announces Adjournment of Annual Meeting and Information for Reconvened Meeting ● Meeting adjourned to November 17, 2022, at 9:00 a.m., Eastern Time ● Soligenix encourages all stockholders as of record July 25, 2022, who have not yet voted,

EXHIBIT 99.1 Soligenix Announces Adjournment of Annual Meeting and Information for Reconvened Meeting ● Meeting adjourned to November 17, 2022, at 9:00 a.m., Eastern Time ● Soligenix encourages all stockholders as of record July 25, 2022, who have not yet voted, to vote by 11:59 p.m., Eastern Time on November 16, 2022 Princeton, NJ – October 20, 2022 – Soligenix, Inc. (Nasdaq: SNGX) (Soligenix or

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 ? Filed by the Registrant ? Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement. ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ? Defin

Regulation FD Disclosure, Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits, Submission of Matters to a Vote of Security Holders

? ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): September 22, 2022 Commission File No. 001-14778 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction

Soligenix Announces Partial Adjournment of Annual Meeting and Information for Reconvened Annual Meeting ● Meeting adjourned to October 19, 2022, at 9:00 a.m., Eastern Time ● Soligenix encourages all stockholders of record at the close of business on

EXHIBIT 99.1 ? Soligenix Announces Partial Adjournment of Annual Meeting and Information for Reconvened Annual Meeting ? ? Meeting adjourned to October 19, 2022, at 9:00 a.m., Eastern Time ? Soligenix encourages all stockholders of record at the close of business on July 25, 2022 who have not yet voted, to vote by 11:59 p.m., Eastern Time on October 18, 2022 ? Princeton, NJ ? September 23, 2022 ?

Soligenix, Inc. 2015 Equity Incentive Plan, as amended on June 18, 2017, September 27, 2018, September 6, 2019 and September 22, 2022.

EXHIBIT 10.1 SOLIGENIX, INC. 2015 EQUITY INCENTIVE PLAN ADOPTED BY THE BOARD OF DIRECTORS ON APRIL 2, 2015 (as amended on June 18, 2017, September 27, 2018, September 6, 2019 and September 22, 2022) The purpose of the Soligenix, Inc. 2015 Equity Incentive Plan (the ?Plan?) is to advance the interests of Soligenix, Inc. by enhancing its ability to attract and retain employees and other persons who

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant x Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ? Definitive

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended June 30, 2022 ☐TRANSITION REPORT PURSUANT TO SEC

Table of Contents ? ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant x Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

TABLE OF CONTENTS UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ? Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement. ? ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

TABLE OF CONTENTS UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ? Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement. ? ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-

Other Events

? ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): July 6, 2022 Commission File No. 000-16929 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of in

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended March 31, 2022 ☐TRANSITION REPORT PURSUANT TO SE

Table of Contents ? ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

Subsidiaries of the Company. *

EXHIBIT 21.1 ? SUBSIDIARIES OF SOLIGENIX, INC. ? The following represents a list of Soligenix, Inc.?s subsidiaries: ? ? ? ? ? ? ? Name Ownership State of Incorporation Enteron Pharmaceuticals, Inc. ? 100.00 % Delaware ? Orasomal Technologies Inc. ? 75.30 % Delaware ? Soligenix BioPharma Canada Incorporated ? 100.00 % Canada ? Soligenix UK Limited ? 100.00 % United Kingdom ? Soligenix NE B.V. ? 100

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the Fiscal Year Ended December 31, 2021 ☐TRANSITION REPORT PURSUAN

Table of Contents ? ? ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

Description of Securities. *

EXHIBIT 4.4 ? SOLIGENIX, INC. DESCRIPTION OF SECURITIES ? The following description of the terms of our securities is not complete and is qualified in its entirety by reference to our Certificate of Incorporation, as amended (the ?Certificate of Incorporation?), and our Bylaws, as amended (the ?Bylaws?), both of which are filed as exhibits to our Annual Reports on Form 10-K. ? Under our Certificat

Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing

? ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 ? FORM 8-K ? CURRENT REPORT ? Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 ? Date of Report (Date of Earliest Event Reported): December 20, 2021 ? Commission File No. 001-14778 ? Soligenix, Inc. (Exact name of small business issuer as specified in its charter) ? ? ? ? DELAWARE ? 41-1505029 (State

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended September 30, 2021 ☐TRANSITION REPORT PURSUANT T

Table of Contents ? ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

Other Events

? ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): October 29, 2021 Commission File No. 000-16929 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction o

Submission of Matters to a Vote of Security Holders

? ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): September 23, 2021 Commission File No. 000-16929 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction

Financial Statements and Exhibits, Other Events

? ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 ? FORM 8-K ? CURRENT REPORT ? Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 ? Date of Report (Date of Earliest Event Reported): September 16, 2021 ? Commission File No. 001-14778 ? Soligenix, Inc. (Exact name of small business issuer as specified in its charter) ? ? ? ? DELAWARE ? 41-1505029 (State

Soligenix to Advance Synthetic Hypericin Development in Psoriasis

Exhibit 99.1 ? ? Soligenix to Advance Synthetic Hypericin Development in Psoriasis ? ? Validated clinical pharmacology and positive psoriasis proof-of-concept clinical study with synthetic hypericin sets stage for pipeline expansion ? Plan to initiate follow-on Phase 2a clinical study in mild-to-moderate psoriasis ? Psoriasis affects 60-125 million people worldwide ? Princeton, NJ ? September 16,

Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing

? ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 ? FORM 8-K ? CURRENT REPORT ? Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 ? Date of Report (Date of Earliest Event Reported): September 16, 2021 ? Commission File No. 001-14778 ? Soligenix, Inc. (Exact name of small business issuer as specified in its charter) ? ? ? ? DELAWARE ? 41-1505029 (State

Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing

? ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 ? FORM 8-K ? CURRENT REPORT ? Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 ? Date of Report (Date of Earliest Event Reported): August 25, 2021 ? Commission File No. 001-14778 ? Soligenix, Inc. (Exact name of small business issuer as specified in its charter) ? ? ? ? DELAWARE ? 41-1505029 (State or

$30 Million Soligenix, Inc. Common Stock

Table of Contents ? Filed Pursuant to Rule 424(b)(5) Registration No. 333-239928 PROSPECTUS SUPPLEMENT (To prospectus dated August 13, 2021) $30 Million Soligenix, Inc. Common Stock We have entered into an at-the-market offering agreement (the ?distribution agreement?), with B. Riley Securities, Inc. (?B. Riley Securities?), dated August 11, 2017 and amended August 28, 2020, relating to shares of

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended June 30, 2021 ☐TRANSITION REPORT PURSUANT TO SEC

Table of Contents ? ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

Financial Statements and Exhibits, Other Events

? ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 ? FORM 8-K ? CURRENT REPORT ? Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 ? Date of Report (Date of Earliest Event Reported): August 13, 2021 ? Commission File No. 001-14778 ? Soligenix, Inc. (Exact name of small business issuer as specified in its charter) ? ? ? ? DELAWARE ? 41-1505029 (State or

Our Definitive Proxy Statement on Schedule 14A, filed with the SEC on August 10, 2021;

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 ? Filed by the Registrant ? Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement. ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ? Definit

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

? ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 ? SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 ? Filed by the Registrant ? ? Filed by a Party other than the Registrant ? ? Check the appropriate box: ? ? Preliminary Proxy Statement. ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 12b-25 NOTIFICATION OF LATE FILING

SEC FILE NUMBER: 001-14778 CUSIP NUMBER: 834223307 UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 12b-25 NOTIFICATION OF LATE FILING (Check One): ? Form 10-K ? Form 20-F ? Form 11-K x Form 10-Q ? Form 10-D ? Form N-CEN ? Form N-CSR For Period Ended: March 31, 2021 ? Transition Report on Form 10-K ? Transition Report on Form 20-F ? Transition Report on Form 11-K ? Transition Report on Form 10-Q For the Transition Period Ended: Nothing in the form shall be construed to imply that the Commission has verified any information contained herein.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended March 31, 2021 ☐ TRANSITION REPORT PURSUANT TO

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended March 31, 2021 or ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File No. 000-16929 SOLIGENIX, INC. (Exact n

Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 7, 2021 Commission File No. 000-16929 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) Delaware 41-1505029 (State or other jurisdiction of incorpo

Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): April 13, 2021 Commission File No. 000-16929 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) Delaware 41-1505029 (State or other jurisdiction of inco

Soligenix Announces Presentations at Prominent Scientific Conferences Key Data Outcomes Presented for HyBryte™ and CiVax™

Exhibit 99.1 Soligenix Announces Presentations at Prominent Scientific Conferences Key Data Outcomes Presented for HyBryte? and CiVax? Princeton, NJ ? April 13, 2021 ? Soligenix, Inc. (Nasdaq: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unmet medical need, announced today planne

Subsidiaries of the Company. *

EXHIBIT 21.1 SUBSIDIARIES OF SOLIGENIX, INC. The following represents a list of Soligenix, Inc.?s subsidiaries: Name Ownership State of Incorporation Enteron Pharmaceuticals, Inc. 100.00 % Delaware Orasomal Technologies Inc. 75.30 % Delaware Soligenix BioPharma Canada Incorporated 100.00 % Canada Soligenix UK Limited 100.00 % United Kingdom Soligenix NE B.V. 100.00 % Netherlands

Annual Report - ANNUAL REPORT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ? ANNUAL REPORT UNDER SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the Fiscal Year Ended December 31, 2020 ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the transition period from to Commission File No. 000-16929 SOLIGENIX, INC. (Exact na

Description of Securities. *

EXHIBIT 4.6 SOLIGENIX, INC. DESCRIPTION OF SECURITIES The following description of the terms of our securities is not complete and is qualified in its entirety by reference to our Certificate of Incorporation, as amended (the ?Certificate of Incorporation?), and our Bylaws, as amended (the ?Bylaws?), both of which are filed as exhibits to our Annual Reports on Form 10-K. Under our Certificate of I

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Soligenix, Inc. 29 Emmons Drive, Suite B-10 Princeton, NJ 08540 January 27, 2021 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, DC 20549 Re: Soligenix, Inc. Registration Statement on Form S-3 Filed January 15, 2021 File No. 333-252153 Ladies and Gentlemen: Pursuant to Rule 461 under the Securities Act of 1933 and on behalf

Investor Presentation – “U.S. Commercialization of SGX301 in the Treatment of Cutaneous T-Cell Lymphoma.”

Exhibit 99.1

Regulation FD Disclosure, Financial Statements and Exhibits - CURRENT REPORT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): January 26, 2021 Commission File No. 000-16929 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of in

- REGISTRATION STATEMENT

As filed with the Securities and Exchange Commission on January 15, 2021 Registration No.

Soligenix Corporate Update Conference Call December 22, 2020 8:30 a.m. Eastern Time

EXHIBIT 99.2 Soligenix Corporate Update Conference Call December 22, 2020 8:30 a.m. Eastern Time Operator Welcome to the Soligenix Corporate Update conference call. At this time all participants are in a listen-only mode. Following management’s prepared remarks, we will hold a Q&A session with the questions submitted by email prior to the call. As a reminder, this is a timed conference call today.

Regulation FD Disclosure, Financial Statements and Exhibits - CURRENT REPORT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): December 22, 2020 Commission File No. 000-16929 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of i

Soligenix Announces Topline Results from its Phase 3 Clinical Trial of SGX942 for the Treatment of Oral Mucositis in Head and Neck Cancer Patients Company to Host Investor Conference Call Today at 8:30AM EST

EXHIBIT 99.1 Soligenix Announces Topline Results from its Phase 3 Clinical Trial of SGX942 for the Treatment of Oral Mucositis in Head and Neck Cancer Patients Company to Host Investor Conference Call Today at 8:30AM EST Princeton, NJ – December 22, 2020 – Soligenix, Inc. (NASDAQ: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused on developing and commercializing pro

Third Amendment to Employment Agreement dated as of December 10, 2020, between Soligenix, Inc. and Christopher J. Schaber, PhD. (incorporated by reference to Exhibit 10.2 included in our current report on Form 8-K filed on December 16, 2020). **

Exhibit 10.2 THIRD AMENDMENT TO EMPLOYMENT AGREEMENT This Third Amendment to Employment Agreement (the “Amendment”) is made and entered into as of December 10, 2020 by and between Soligenix, Inc., a Delaware corporation having a place of business at 29 Emmons Drive, Suite B-10, Princeton, NJ 08540 (the “Corporation”), and Christopher J. Schaber, Ph.D. (the “Employee”). RECITALS WHEREAS, the Corpor

Soligenix Announces $20 Million Strategic Convertible Debt Financing Agreement with Pontifax Medison Debt Financing ● Extends cash runway through 2022 ● Debt can be converted into equity at a price of $4.10 per share

Exhibit 99.1 Soligenix Announces $20 Million Strategic Convertible Debt Financing Agreement with Pontifax Medison Debt Financing ● Extends cash runway through 2022 ● Debt can be converted into equity at a price of $4.10 per share Princeton, NJ – December 16, 2020 – Soligenix, Inc. (Nasdaq: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused on developing and commercial

Loan and Security Agreement, dated December 15, 2020. (incorporated by reference to Exhibit 10.1 included in our current report on Form 8-K filed on December 16, 2020).

Exhibit 10.1 LOAN AND SECURITY AGREEMENT THIS LOAN AND SECURITY AGREEMENT is made and dated as of December 15, 2020 and is entered into by and between Soligenix, Inc., a corporation incorporated in the State of Delaware, and each of its Subsidiaries from time to time party hereto, including the Subsidiaries set forth on Schedule I hereto (collectively referred to as “Borrower”), Pontifax Medison F

Registration Rights Agreement, dated December 15, 2020 by and among Soligenix, Inc. and the other parties named therein (incorporated by reference to Exhibit 4.1 included in our current report on Form 8-K filed on December 16, 2020).

Exhibit 4.1 REGISTRATION RIGHTS AGREEMENT This REGISTRATION RIGHTS AGREEMENT (this “Agreement”) is made and entered into as of December 15, 2020 by and among Soligenix, Inc., a corporation incorporated in the State of Delaware (the “Company”), and the “Lenders” named in that certain Loan and Security Agreement by and among the Company and the Lenders, dated December 15, 2020 (the “Loan Agreement”)

Entry into a Material Definitive Agreement, Unregistered Sales of Equity Securities, Financial Statements and Exhibits, Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): December 10, 2020 Commission File No. 000-16929 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) Delaware 41-1505029 (State or other jurisdiction of i

Certificate of Amendment to Second Amended and Restated Certificate of Incorporation (incorporated by reference to Exhibit 3.1 of amendment number 1 to current report on Form 8-K filed on December 3, 2020).

Exhibit 3.1 CERTIFICATE OF AMENDMENT TO SECOND AMENDED AND RESTATED CERTIFICATE OF INCORPORATION THE UNDERSIGNED, being a duly appointed officer of Soligenix, Inc. (the “Corporation”), a corporation organized and existing under and by virtue of the Delaware General Corporation Law of the State of Delaware (the “DGCL”), for the purpose of amending the Corporation’s Second Amended and Restated Certi

Financial Statements and Exhibits, Submission of Matters to a Vote of Security Holders, Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year - AMENDMENT NO. 1 TO FORM 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K/A CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): November 27, 2020 Commission File No. 000-16929 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of

- CURRENT REPORT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): November 23, 2020 Commission File No. 000-16929 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of i

Submission of Matters to a Vote of Security Holders - CURRENT REPORT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): November 23, 2020 Commission File No. 000-16929 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of i

Quarterly Report - FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended September 30, 2020 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File No. 000-16929 SOLIGENIX, INC. (Exa

Third Extension and Amendment to Lease dated July 7, 2020 between CPP II LLC and Soligenix, Inc. (incorporated by reference to Exhibit 10.1 included in our Quarterly Report on Form 10-Q for the fiscal quarter ended September 30, 2020).

Exhibit 10.1 THIRD EXTENSION AND AMENDMENT TO LEASE THIS THIRD EXTENSION AND AMENDMENT TO LEASE made as of this 7th day of July 2020, by and between CPP II LLC, a Delaware limited liability company, with an address at c/o Oestreicher Properties Inc., 430 Park Avenue, 5th Floor, New York, New York 10022(“Landlord”), and SOLIGENIX, INC., a corporation organized and existing under the laws of the Sta

- DEFINITIVE PROXY STATEMENT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement. ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☒ Definitiv

- PELIMINARY PROXY STATEMENT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☒ Preliminary Proxy Statement. ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitiv

Certificate of Amendment to Second Amended and Restated Certificate of Incorporation.

Exhibit 3.1 CERTIFICATE OF AMENDMENT TO SECOND AMENDED AND RESTATED CERTIFICATE OF INCORPORATION THE UNDERSIGNED, being a duly appointed officer of Soligenix, Inc. (the “Corporation”), a corporation organized and existing under and by virtue of the Delaware General Corporation Law of the State of Delaware (the “DGCL”), for the purpose of amending the Corporation’s Second Amended and Restated Certi

Financial Statements and Exhibits, Submission of Matters to a Vote of Security Holders, Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year - CURRENT REPORT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): September 16, 2020 Commission File No. 000-16929 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) DELAWARE 41-1505029 (State or other jurisdiction of

COVID - 19 Landscape and Applications NASDAQ: SNGX Forward - Looking Statements This presentation contains forward - looking statements . All statements other than statements of historical facts contained in this presentation, including statements re

Exhibit 99.2 COVID - 19 Landscape and Applications NASDAQ: SNGX Forward - Looking Statements This presentation contains forward - looking statements . All statements other than statements of historical facts contained in this presentation, including statements regarding our future results of operations and financial position, business strategy, prospective products and product candidates and their

Financial Statements and Exhibits, Other Events - CURRENT REPORT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): September 10, 2020 Commission File No. 000-16929 Soligenix, Inc. (Exact name of small business issuer as specified in its charter) Delaware 41-1505029 (State or other jurisdiction of