UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 8-K/A

(Amendment No. 1)

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 22, 2015

Cartesian, Inc.

(Exact name of registrant as specified in its charter)

7300 College Boulevard, Suite 302

Overland Park, Kansas 66210

(Address of principal executive office)(Zip Code)

(913) 345-9315

(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 of the registrant under any of the following provisions:

Explanatory Note

This Amendment No. 1 on Form 8-K/A (“Amendment”) is being filed to amend and supplement the Current Report on Form 8-K filed by Cartesian, Inc. (the “Company”) with the Securities and Exchange Commission on July 23, 2015 (the “Initial Form 8-K”), in order to include financial statements and pro forma financial information permitted to be excluded from the Initial Form 8-K and filed by amendment to the Initial Form 8-K. As previously reported in the Initial Form 8-K, the Company acquired all of the outstanding capital stock of Farncombe France SARL, an entity formed under the laws of France, and Farncombe Technology Limited, a company incorporated and registered in England and Wales (which includes its wholly-owned subsidiary, Farncombe Engineering Services Limited, a company incorporated and registered in England and Wales) (collectively, the “Farncombe Entities”). Farncombe Engineering Services Limited became a wholly-owned subsidiary of Farncombe Technology Limited immediately prior to the Closing of the acquisition of Farncombe Technology Limited by Cartesian. This Amendment provides the audited historical financial statements of the Farncombe Entities pursuant to Item 9.01(a) of Form 8-K and the unaudited pro forma financial information required by Item 9.01(b) of Form 8-K. Except for the filing of such financial statements, pro forma financial information and the accompanying consents of independent accountants, this Amendment does not modify or update the Initial Form 8-K.

The aggregate amount of purchase consideration paid at the Closing of the acquisition of the Farncombe Entities consisted of cash in the amount of £654,093 pounds sterling (approximately US$1.0 million based on an exchange rate of £1.556= US$1.00 as of July 21, 2015) and 588,567 shares of Company Common Stock. Additional consideration is payable upon determination of the net working capital of the Farncombe Entities and is expected to equal at least £654,093 pounds sterling (approximately US$1.0 million based on an exchange rate of £1.556= US$1.00 as of July 21, 2015), and will be adjusted as provided in the Purchase Agreement based upon the relative amounts of the net working capital of the Farncombe Entities as of May 31, 2015 and as of Closing and as compared to the target amount of net working capital specified in the Purchase Agreement.

The audited financial statements of Farncombe France SARL, an entity formed under the laws of France, Farncombe Technology Limited, a company incorporated and registered in England and Wales and Farncombe Engineering Services Limited, a company incorporated and registered in England and Wales for the year ended December 31, 2014 are attached hereto as Exhibit 99.2, 99.3 and 99.4, respectively and incorporated in their entirety herein by reference.

The financial statements of Farncombe Technology Limited and Farncombe Engineering Services Limited were prepared in accordance with accounting principles generally accepted in the United Kingdom (“UK GAAP”) and the financial statements of Farncombe France SARL were prepared in accordance with International Financial Reporting Standards (“IFRS”) as issued by the International Accounting Standards Board, both of which differ in certain respects from U.S. GAAP. The differences in accounting treatment between UK GAAP and IFRS, on the one hand, and U.S. GAAP, on the other hand, applicable to the Farncombe Entities are described in the notes to the unaudited pro forma combined condensed financial statements attached hereto as Exhibit 99.5.

The required pro forma combined condensed balance sheet as of July 4, 2015 and unaudited pro forma combined condensed statements of income for the fiscal year ended January 3, 2015 and the twenty-six weeks ended July 4, 2015 are attached hereto as Exhibit 99.5 and are incorporated in its entirety herein by reference.

The following exhibits are filed as part of this Amendment.

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.

Date: October 7, 2015

EXHIBIT INDEX