UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or Section 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): May 10, 2021

ARCLIGHT CLEAN TRANSITION CORP. II

(Exact name of registrant as specified in its charter)

200 Clarendon Street, 55th Floor

Boston, MA, 02116

(Address of principal executive offices)

(617) 531-6300

Registrant’s telephone number, including area code

Not Applicable

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation to the registrant under any of the following provisions:

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 or Rule 12b-2 of the Securities Exchange Act of 1934.

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.  ☐

On May 10, 2021, ArcLight Clean Transition Corp. II (the “Company”) announced that the holders of the Company’s units (the “Units”) may elect to separately trade the Class A ordinary shares, par value $0.0001 per share (the “Class A ordinary shares”), and warrants included in the Units commencing on May 13, 2021. Each Unit consists of one Class A ordinary share and one-fifth of one redeemable warrant to purchase one Class A ordinary share. Any Units not separated will continue to trade on the Nasdaq Capital Market (“Nasdaq”) under the symbol “ACTDU”. Any underlying Class A ordinary shares and warrants that are separated will trade on the Nasdaq under the symbols “ACTD” and “ACTDW,” respectively. No fractional warrants will be issued upon separation of the Units and only whole warrants will trade. Holders of Units will need to have their brokers contact Continental Stock Transfer & Trust Company, the Company’s transfer agent, in order to separate the holders’ Units into Class A ordinary shares and warrants.

A copy of the press release issued by the Company announcing the separate trading of the securities underlying the Units is attached hereto as Exhibit 99.1.

(d) Exhibits.

SIGNATURE

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.

Dated: May 10, 2021

Exhibit 99.1

ArcLight Clean Transition Corp. II Announces the Separate Trading of its Class A Ordinary Shares and Warrants Commencing May 13, 2021

Boston, Massachusetts, May 10, 2021— ArcLight Clean Transition Corp. II (Nasdaq: ACTDU) (the “Company”) announced today that, commencing May 13, 2021, holders of the units sold in the Company’s initial public offering of 27,500,000 units, completed on March 22, 2021, and the subsequent sale of an additional 3,616,305 units upon partial-exercise of the underwriters’ over-allotment option, on March 25, 2021, may elect to separately trade the Class A ordinary shares and warrants included in the units. Those units not separated will continue to trade on the Nasdaq Capital Market (“Nasdaq”) under the symbol “ACTDU,” and the Class A ordinary shares and warrants that are separated will trade on the Nasdaq under the symbols “ACTD” and “ACTDW,” respectively. Holders of units will need to have their brokers contact Continental Stock Transfer & Trust Company, the Company’s transfer agent, in order to separate the units into Class A ordinary shares and warrants.

The units were initially offered by the Company in an underwritten offering. Barclays Capital Inc. and Citigroup Global Markets Inc. are serving as joint book-running managers for the offering. A registration statement relating to the units and the underlying securities was declared effective by the Securities and Exchange Commission (the “SEC”) on March 22, 2021.

This press release shall not constitute an offer to sell or the solicitation of an offer to buy the securities of the Company, nor shall there be any sale of these securities in any state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction. The offering was made only by means of a prospectus. Copies of the prospectus may be obtained from Citigroup Global Markets Inc., c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, New York 11717, Telephone: 1-800-831-9146; or Barclays Capital Inc., c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, New York 11717, Telephone: 1-800-603-5847.

About ArcLight Clean Transition Corp. II

ArcLight Clean Transition Corp. II, led by Chairman Daniel Revers and President and Chief Executive Officer Jake Erhard, intends to pursue opportunities created by the accelerating transition toward sustainable use of energy and natural resources, but will not be limited to a particular industry or geographic region in its identification and acquisition of a target company.

Forward-Looking Statements

This press release may include “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. All statements other than statements of historical fact included in this press release are forward-looking statements. When used in this press release, words such as “anticipate,” “believe,” “estimate,” “expect,” “intend” and similar expressions, as they relate to us or our management team, identify forward-looking statements. Such forward-looking statements are based on the beliefs of management, as well as assumptions made by, and information currently available to, the Company’s management. Actual results could differ materially from those contemplated by the forward-looking statements as a result of certain factors detailed in the Company’s filings with the SEC. All subsequent written or oral forward-looking statements attributable to us or persons acting on our behalf are qualified in their entirety by this paragraph. Forward-looking statements are subject to numerous conditions, many of which are beyond the control of the Company, including those set forth in the Risk Factors section of the Company’s registration statement and prospectus relating to the Company’s initial public offering filed with the SEC. The Company undertakes no obligation to update these statements for revisions or changes after the date of this release, except as required by law.

Media inquiries:

Marco Gatti, CFO

617-531-6300

investor.relations@arclightclean.com