Boston-based Cabot, Cabot & Forbes has proposed renovating the former St. Gabriel’s Monastery in Brighton and adding four new multifamily buildings.

The project would add a total of 610,000 square feet to the 12-acre site.

A partnership including Chicago-based Blue Vista acquired the two parcels at the corner of Commonwealth Avenue from St. Elizabeth’s Hospital in December for $21 million.

The St. Gabriel’s Monastery would be the “focal point” of the 680-unit project and four new buildings would be built ranging from four to seven stories at the rear of the site overlooking Brighton High School, according to a letter to the Boston Redevelopment Authority by Cabot, Cabot & Forbes CEO Jay Doherty.

The residences would serve graduate students, teachers, trainers and researchers “in a wide variety of professions” and free up housing for families in Brighton, the letter states. Landscaping would be retained to serve as a buffer from surrounding residential areas and the new buildings would be built toward the rear of the site in areas primarily used for surface parking.

Cabot, Cabot & Forbes bills the project as transit-friendly with the nearest MBTA Green Line station approximately 1,500 feet away. The development would include 400 parking spaces.

The company has specialized in transit-oriented multifamily development recently including the 428-unit Atmark luxury apartment complex that opened in 2013 near the MBTA’s Alewife station in Cambridge and the 180-unit Deco apartment complex, which opened in March across from the Quincy Adams station in Quincy.