Five years after the Harvard Square Theater closed its curtains, Cambridge city officials are pushing the owners of the long-vacant Church St. property to come up with a plan for its future soon—and threatening to seize the site if they do not.

Billionaire investor Gerald Chan—who co-founded the Morningside Group—bought the property in 2015 from real estate developer Richard L. Friedman, who had acquired it after the theater closed in July 2012. A Harvard Square staple since 1925, the theater has remained vacant since 2012.

At its Feb. 27 meeting, the Cambridge City Council decided to take up the issue, requesting that City Manager Louis A. DePasquale notify Morningside and Chan to submit long term plans for the property within 30 days.

According to Harvard professor Suzanne P. Blier, who has been active in Harvard Square conservation efforts, the Council discussed harsh measures if this is not achieved—including obtaining the property by eminent domain, where the city would take over the building.

Chan, a Harvard benefactor who donated a then-record $350 million to the School of Public Health in 2014, also owns several other multi-million dollar properties in Harvard Square. Morningside Group could not be reached for comment, but told the Council in December that it would present a plan for the building this spring.

Denise A. Jillson, executive director of the Harvard Square Business Association, said she was concerned about the economic impact a large vacant building has on the Square.

“That’s what matters to the community because that’s a very long time for such a large parcel to be dark in the heart of Harvard Square,” Jillson said. “The adverse economic impact that a dark building has on the other businesses on the street, as well as throughout the Square, cannot be dismissed.”

Blier and Jillson said foot traffic lost to the vacant theater has adversely affected other businesses on Church St., including the nearby Mongolian grill-style restaurant FiRE+iCE, which closed in Sept. 2016.

Jillson said even if plans were started now, the slow pace of change in Cambridge would delay efforts. After public meetings and permitting, it could be another two or three years until the property opened, she said.

“I think that what the Council is trying to do is to really send a message, not only to the owner of the theater, but to the owners of other parcels throughout the city that are inactive and dark,” Jillson said.

Blier said she hopes celebrities—like Boston natives Ben Affleck and Matt Damon, who had previously worked at the theater—and musicians who have visited and performed at the theater might rally behind its reopening.

“If we can get group of supporters involved, maybe even Bruce Springsteen, or John Lithgow to see what we could do to put together a plan to renovate and reopen the theater, either in its original larger form or divided into smaller spaces, it would be great,” Blier said.

Jillson said she is optimistic about the plans that she anticipates Morningside will lay out soon. She hopes the property will become a mixed-use building, she added.

“When [Chan] does something, he does it very, very nicely,” Jillson said. “I really trust him to do something wonderful, because if you look at some of the other buildings that he’s already restored here in Harvard Square, his team does very, very nice work.”

“The point is that whatever that is, it should happen sooner rather than later,” Jillson added.

–Staff writer Alison W. Steinbach can be reached at alison.steinbach@thecrimson.com. Follow her on Twitter @alisteinbach.

—Staff writer Katherine E. Wang can be reached at katie.wang@thecrimson.com. Follow her on Twitter @katiewang29.