Image courtesy of CBT Architects

How much would you pay for a small parking lot and 3-story office building next to the Sullivan Square rotary?

RISE Together this week acquired four properties on Cambridge and Sever streets spanning 0.42 acres and valued at $13 million, including the Teamsters Union Local 25 offices. A multifamily building is planned on the site, according to a statement from the development team.

Developers RISE Together and TRAX notified Boston officials last September of plans for a 2.6 million-square-foot mixed-use development spanning nearly 13 acres on Cambridge, Carter and Crescent streets near the Boston-Somerville line. Developers propose 1.7 million square feet of office-lab space, a 200-room hotel and 851 housing units.

The Teamsters’ building and its parking lot are not part of the first 1 million-square-foot phase of the project, as described by developers in the September notification letter. That phase will include 906,000 square feet of office-lab space and 160 housing units on 6 acres located west of Interstate 93.