Material Event (Form 8-K)

Item 8.01 Other Events.

On May 28, 2026, Soligenix, Inc. (the "Company") filed a prospectus supplement (the "Current Prospectus Supplement") to increase the maximum aggregate offering amount of the shares of the Company's common stock, par value $0.001 per share, issuable under the At Market Issuance Sales Agreement dated January 23, 2026 (the "Sales Agreement") with Rodman & Renshaw LLC, by an additional aggregate amount of $2,956,000. The Company previously sold approximately $3,445,000 of shares of common stock pursuant to the Sales Agreement under a prior prospectus supplement. A copy of the legal opinion as to the legality of the $2,956,000 of shares of common stock issuable under the Sales Agreement and covered by the Current Prospectus Supplement is filed as Exhibit 5.1 attached hereto.

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