Mack-Cali Realty Corp. struck two deals for the sale of its 56-building office/flex portfolio encompassing 3.1 million square feet for $487.5 million.

The company said the sale would mark the completion of its repositioning to become a waterfront-centric office and residential landlord.

Under the terms of the definitive agreements, Robert Martin Co. LLC affiliate RMC Acquisition Entity LLC will acquire the portfolio, with closing expected early in the second quarter.

Mack-Cali will use the sale proceeds to repay approximately $230 million of unsecured debt and to acquire the 377-unit Soho Lofts apartment community in Jersey City, N.J.