Image courtesy of BPDA

The Boston Planning & Development Agency board of directors approved conversion of a Downtown Crossing office building into 255 apartments in the final meeting for its longest-tenured member, Ted Landsmark.

Mayor Michelle Wu took the unusual step of attending the meeting to acknowledge Landsmark’s “legendary influence” on the city.

“I know you have counseled mayor after mayor, leader after leader across every sector in the city,” Wu said, before declaring Thursday as Dr. Ted Landsmark Day in Boston.

An architect, attorney and Northeastern University professor, Landsmark was appointed to the then-Boston Redevelopment Authority board by former Mayor Marty Walsh in 2014.

He became part of a symbol of Boston’s racial strife in 1976 when he was attacked near Boston City Hall by an anti-school busing protester wielding an American flag. News photographer Stanley Forman captured the image in a Pulitzer Prize-winning photograph, “The Soiling of Old Glory.”

During Landsmark’s time on the board, the BPDA approved 138 million square feet of development worth an estimated $48.7 billion.

In a light monthly meeting agenda, the board approved Boston-based developer Synergy’s $133 million conversion of an 11-story, 219,200 square-foot office building at 280-300 Washington St. into 255 apartments.

The building’s 44 income-restricted units will be reserved for households earning a maximum 60 percent of area median income, and another eight will be set aside for federal housing voucher-holders. Rents for 18 affordable units will start at $1,266.

Market-rate units are expected to rent for $5 to $6 per square foot, Synergy Senior Vice President Will Grosvenor said.

Designed by Gensler, the project will retain 12,200 square feet of retail space, and add a residential lobby and amenities.

The project is the largest single residential conversion submitted under Boston’s tax incentive program, which has received applications to convert 1.5 million square feet of office space in 29 buildings into 1,700 apartments.

Projects approved under the program receive 75 percent property tax abatements for 29 years. Applications are open until Dec. 31.

The board also approved conversion of three floors at 69 A St. in South Boston into 24 residential units designated for the Council on International Educational Exchange’s post-graduate interns.

Photo courtesy of Synergy