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 18, 2025

Registrant’s telephone number, including area code: (703) 980-4182

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ¨

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

Item 4.01 Changes in Registrant’s Certifying Accountant.

Based on information provided by Marcum LLP (“Marcum”), the independent registered public accounting firm of Quoin Pharmaceuticals Ltd. (the “Company”), CBIZ CPAs P.C. (“CBIZ CPAs”) acquired the attest business of Marcum, effective November 1, 2024. Marcum continued to serve as the Company’s independent registered public accounting firm through March 18, 2025. On March 18, 2025, Marcum resigned as the Company’s independent registered public accounting firm, and CBIZ CPAs was engaged to serve as the independent registered public accounting firm of the Company for the year ending December 31, 2025, effective immediately. The engagement of CBIZ CPAs was approved by the Audit Committee of the Company’s Board of Directors. The services previously provided by Marcum will now be provided by CBIZ CPAs.

Marcum’s reports on the Company’s consolidated financial statements for the fiscal years ended December 31, 2024 and 2023 did not contain an adverse opinion or a disclaimer of opinion and were not qualified or modified as to uncertainty, audit scope or accounting principles.

During the Company’s two most recent fiscal years ended December 31, 2024 and 2023, and the subsequent interim period through March 18, 2025, there were no disagreements (as defined in Item 304(a)(1)(iv) of Regulation S-K and the related instructions to Item 304 of Regulation S-K) between the Company and Marcum on any matter of accounting principles or practices, financial statement disclosure, or auditing scope or procedure, which disagreements, if not resolved to the satisfaction of Marcum, would have caused Marcum to make reference to the subject matter of the disagreements in connection with its reports on the Company’s consolidated financial statements for such years. In addition, during the Company’s two most recent fiscal years ended December 31, 2024 and 2023, and the subsequent interim period through March 18, 2025, there were no “reportable events,” as defined in Item 304(a)(1)(v) of Regulation S-K.

During the fiscal years ended December 31, 2024 and 2023 and through March 18, 2025, neither the Company nor anyone on its behalf consulted with CBIZ CPAs regarding (i) the application of accounting principles to any specified transaction, either completed or proposed or the type of audit opinion that might be rendered on the Company’s consolidated financial statements, and neither a written report nor oral advice was provided to the Company that CBIZ CPAs concluded was an important factor considered by the Company in reaching a decision as to any accounting, auditing, or financial reporting issue, or (ii) any matter that was either the subject of a “disagreement,” as defined in Item 304(a)(1)(iv) of Regulation S-K, or a “reportable event,” as defined in Item 304(a)(1)(v) of Regulation S-K.

The Company provided Marcum with a copy of the above disclosures and requested that Marcum furnish the Company with a letter addressed to the Securities and Exchange Commission stating whether or not it agrees with the statements made above. A copy of Marcum’s letter dated March 20, 2025 is attached as Exhibit 16.1 to this Current Report on Form 8-K.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, hereunto duly authorized.