Material Event - Form 425

On April 18, 2024, Atlantic Coastal Acquisition Corp. II (the "Company") received letters from the Nasdaq Stock Market LLC ("Nasdaq") indicating that (i) the Company was not in compliance with Nasdaq's Listing Rule 5450(b)(1)(B) because the Company has not, as of the fiscal year ended December 31, 2023, maintained a minimum of 1,100,000 publicly held shares, as required under the Nasdaq continued listing standards for The Nasdaq Global Market and (ii) the Company has failed to maintain a minimum market value of publicly held shares of $15,000,000 for the 30 consecutive business day period preceding this letter, as required under Nasdaq Listing Rule 5450(b)(2)(C).

Under Nasdaq Listing Rules, the Company has 45 calendar days to submit a plan to regain compliance with Rule 5450(b)(1)(B) and 180 calendar days to regain compliance with Rule 5450(b)(2)(C). The Company expects that both deficiencies will be cured as a result of the consummation of its previously announced proposed business combination with Abpro Corporation (the "Business Combination") as described in the Company's Current Report on Form 8-K filed with the Securities and Exchange Commission ("SEC") on December 12, 2023. On April 23, 2024, the Company submitted its plan of compliance to Nasdaq, where it requested an extension of the compliance period to regain compliance with Rule 5450(b)(1)(B) from 45 calendar days to 180 calendar days.