The Croft School, a private elementary school, is taking over the former Stella Restaurant space on the ground floor of 1525 Washington Street in the South End. This is disappointing because Stella was really the only interesting street-level presence along this stretch of Washington.
This stretch is dead mostly because of the city. The Blackstone School could not have a worse Washington Street presence. It's mostly a giant surface parking lot. The small part of the school that is on Washington is a giant blank windowless brick wall. Across the street is a large 1950-era inward-facing public housing complex, the Salvation Army, and what appears to be an abandoned post office (probably utilized by the housing complex today). About 10 years ago, the City opted to use stimulus funds to simply renovate the housing units instead of attempting to redevelop them into something that would help activate the street a bit.
It's unfortunate because this stretch opens on to to the Blackstone/Franklin Square parks and its currently such a dead space. Immediately north and south there are healthy pockets of activity on Washington.