The sale of Midtown’s Kirby Mansion to a group connected with a Cadillac dealership has left local preservationists with one last option: Convince the new owner that it makes financial sense not to tear it down.

They already have mounted a public campaign touting the 1920s English-style manor as a valued piece of Houston history that should be saved. They’ve gotten the word out about its original owner, John Henry Kirby, an entrepreneur noted as “Houston’s first tycoon.”

They have included the mansion, one of the few residential estates still standing in the downtown area, on architectural tours of the city’s oldest buildings.

Yet the property, which has never been designated as a city, state or federal landmark, faces an uncertain future. An entity affiliated with the nearby Central Houston Cadillac dealership took ownership of the mansion this month, according to a deed recorded in the Harris County Clerk’s office.

For two days, officials with the dealership at 2520 Main and its holding company, Nicpa Holdings, have not responded to requests from the Chronicle for comment. Neither has the mansion’s longtime former owner, attorney Philip Azar, who has used the building for law offices.

PREVIOUSLY ON HOUSTONCHRONICLE.COM: Fears mount as rumors spread that Kirby Mansion close to sold

David Bush, executive director for Preservation Houston, a 40-year-old nonprofit that advocates for the revitalization of old buildings, says the group will take the case for saving the mansion directly to the new owners.

“We’re sort of beyond the point of saying this is a significant building, associated with Kirby and important architecture and everything,” Bush said. “Really what our job is right now is to explain to the new owner the advantages of historic preservation for his business.”

Uncertainty over the mansion’s future has fueled concerns. In June, Preservation Houston contacted its members to inform them the building was in peril, explaining that the property was under contract and that “reliable sources” indicated the new owner did not intend to retain the building.

Before the sale closed, preservation advocates met with Azar to discuss options for maintaining the structure.

Minnette Boesel, who was in one of those meetings, said she hopes the new ownership will consider the value of preserving the property, particularly given its location near Interstate 45.

Plans to realign the freeway, and a proposal to turn the Pierce Elevated into an elevated park like the High Line in New York, put the Kirby Mansion in a unique position to benefit, said Boesel, who chairs the Houston Archaeological and Historical Commission.

The red-brick mansion at 2000 Smith is eligible for multiple historic designations from the local to the federal level as well as tax credits that could help finance its rehabilitation.

In addition to the financial incentives, restoring the structure would build good will in the community, Bush said.

RELATED: W Hotel proposal for downtown moves into next phase

In early 2017, another auto dealer purchased the historic Rice Mansion, also in Midtown, only to tear it down.

In that case, Group 1 Automotive acquired the property from Mathew Knowles, the father of Houston-born superstars Beyoncé and her sister Solange.

Knowles said at the time that he offered the property to the city of Houston and Rice University before selling it.

Earlier this month, Azar transferred ownership of the Kirby Mansion to Central Houston Auto Properties II LLC.

Representatives of Preservation Houston have reached out to the new ownership, which includes Houston businessman Ricardo Weitz.

“We have made the preliminary approaches,” Bush said.

Bush noted Tuesday that the neighborhood around the mansion is poised to change dramatically.

“Whether the Pierce Elevated comes down and it’s a boulevard or is some kind of park like the High Line, owning the mansion and having that as your image would really be beneficial for your business,” he said.

The Midtown property is valued at $3.9 million by Harris County Appraisal District. The building is on a 62,500-square-foot block just south of the Pierce Elevated, the section of Interstate 45 that separates downtown from Midtown. The site is bounded by Brazos, Pierce, Smith and Gray.

RELATED: Fitzgerald's property in the Heights gets new owner

The 18,000-square-foot building was constructed for John Henry Kirby, a “lawyer, lumberman and entrepreneur from East Texas who emerged at the turn of the 20th century as Houston’s first tycoon,” according to Stephen Fox’s AIA Houston Architectural Guide.

Kirby and his family had lived on the site in a Victorian home since 1897 but later remodeled and added onto the house. A second addition was designed by architect James Ruskin Bailey, resulting in the 36-room Tudor Revival-style building, according to Preservation Houston.

Kirby died in 1940, and the house was sold in 1947. For the next three decades, it was housed the Houston-Harris County Red Cross. It has been used as office space since the late 1970s.

In recent years, at least two other groups have attempted to purchase and restore the property, but neither proposal came to fruition.

More recently, John Deveau, owner of Sara’s Inn, a bed and breakfast in a old Victorian home in the Heights, expressed interest in buying the property for a boutique hotel when he heard it might be selling. By that time, he was too late.

“Phil had done a very good job of keeping the house nice,” Deveau said. “He was gracious enough to give us a tour.”

nancy.sarnoff@chron.com

twitter.com/nsarnoff