Socialite Elizabeth Graham Lindemann, the ex-wife of art collector Adam Lindemann, has bought a bachelorette pad at 730 Park Avenue. She paid $10.5 million for the 11-room co-op, $1 million less than the asking price.

The apartment is one floor below the home she once shared with her husband; Ms. Lindemann sold that apartment in June for $21.5 million to hedge-fund manager Ottavio Frank Biondi Jr. (no relation to the ex-Viacom C.E.O.), whose new 5,600-square-foot apartment has full views of Park Avenue.

Ms. Lindemann will have to settle for north, south and west exposures—plus a wood-paneled library with a wood-burning fireplace, a drawing room (ditto the fireplace), a formal dining room and three staff rooms

Then there’s the master bedroom with something called a loggia. We turn now to Corcoran superbroker and senior vice president Sharon Baum, who said she wouldn’t confirm the identities of the buyer or seller, which are listed in city records, but would tell us what a loggia is.

“Depending on how large they are, you might call it a sun room or a conservatory. Or a greenhouse,” Ms. Baum said. “All glass, floor to ceiling, and it’s open.”

Ms. Lindemann bought her apartment from the estate of telecommunications magnate Charles Wohlstetter, which was represented by Ms. Baum. Wohlstetter formed Contel in 1961, which grew into a $6 billion company by the time it was acquired by GTE in 1991. He passed away in 1995; Rose Wohlstetter, his widow, died this May.

“I hate the word ‘volume,’” said Ms. Baum. “But the volume was so great—just a very gracious apartment.”

Ms. Lindemann has reportedly been dating financier Todd Meister, the ex-husband of hotel heiress Nicky Hilton, whom he married in 2004 before getting an annulment weeks later.

Sotheby’s International Realty broker Serena Boardman, who represented Ms. Lindemann, would not comment.

The building is famous for at least one reason: Along with 985 Park, 730 was a haven for Jewish New Yorkers when anti-Semitism was the norm for “good” New York co-ops—“right up until the late 70’s, maybe even early 80’s,” said a broker who did high-end deals back then.

As for Adam Lindemann: This June, he married former model Amalia Dayan, the granddaughter of the Israeli Defense Minister Moshe Dayan. They are reportedly living in the Time Warner Center, where they share space with pop masterpieces by Andy Warhol, Jeff Koons and Damien Hirst.

At 77 East 77th, a few blocks up from his old Park Avenue apartment, Mr. Lindemann bought a Beaux-Arts carriage house in 2004. He paid $6.75 million for the building, built by A.M. Welch in 1897, and in January 2006 put it back on the market for $14 million. But after only 26 days on the market, Mr. Lindemann pulled the house back off. Guess who handled the property? Ms. Boardman—who, once again, would not comment.