Leaders of the Painted Bride Art Center argued in Philadelphia Orphans’ Court on Tuesday that the organization should be allowed to sell its building to the highest bidder — despite the virtual certainty that such a sale would mean destruction of the city’s oldest alternative arts space and the famous Isaiah Zagar mosaics that sheath the walls.

Testifying before Judge Matthew D. Carrafiello, Painted Bride executive director Laurel Raczka said that “maintaining the building is no longer sustainable” and that the $4.8 million sale to developers led by Groom Investments is the only way for the organization to make ends meet over the long term. Raczka said entertaining a lesser $2.6 million offer by Lantern Theater Company that would preserve the venue for performance and save the Zagar mosaics would not be responsible.

“We need the full resources of the market value of our building,” Raczka said.

Groom Investment has filed plans with the city indicating it would replace the building and Zagar’s artwork, located in the shadow of the Ben Franklin Bridge at 230 Vine St., with condos and parking.

The hearing, which the Bride sought to get the imprimatur of the court to its plan, was attended by several participants who have filed a petition in opposition to the plan and seeking replacement of the Bride’s entire board of directors with an “interim board” devoted to “revitalizing the Painted Bride.”

Joan Myers Brown, founding director of Philadanco, one of those who would step in as part of an “interim board,” said a replacement for the Painted Bride would be “hard to find.”

Brown, 87, started working with the Bride in the early 1970s, she said, teaching dance and working out her early choreography. “I kind of feel I’m the grandmother of the Painted Bride,” she said. “It was a crutch for us … to begin our company.”

Brown said that “so many artists are dependent on the Painted Bride” as a venue, its loss would be felt across the city. “I’d hate to see that happen.”

Kathleen Foster, curator of American art for the Philadelphia Museum of Art, told the court that the mosaics and Zagar are unique and that their destruction would be astonishing.

“The Painted Bride is a great work of art,” Foster said. “I have to say I’m appalled that a nonprofit would tear down a work of art created on their behalf.”

After the hearing, Raczka was asked if she considered the Zagar mosaics as art. “Absolutely,” she said. “My work is to maintain the mission of the Painted Bride.”

Carrafiello said he would make a decision on the sale within a week or two.

In a statement, the office of Pennsylvania Attorney General Josh Shapiro said it did not anticipate filing any objection to the Bride sale.