Guess Who’s Going to N.Y.?

Academy Award-winning actor SIDNEY POITIER and his wife, Joanna, have sold their Beverly Hills home of 19 years and have purchased a co-op in a pre-World War II building in New York City, sources say.

Poitier, 70, was the first African American to win a best actor Oscar (“Lilies of the Field” in 1963), and he was the first man of color to win the American Film Institute’s Life Achievement Award, in 1992.

Last fall, he and singer Harry Belafonte were winners of the first Thurgood Marshall Lifetime Achievement Award, presented by the NAACP Legal Defense and Education Fund. Poitier played the late Supreme Court justice in the 1991 miniseries “Separate But Equal.”

Poitier, also a director (“Fast Forward,” “Ghost Dad”), has starred in dozens of films, including “Sneakers” (1992), “Guess Who’s Coming to Dinner?” (1967) and “A Raisin in the Sun” (1961), in which he also starred on Broadway.

Joanna Poitier, an actress in France before she married Poitier more than 22 years ago, is an interior designer who has decorated a number of celebrities’ homes in Los Angeles.

The Poitiers aren’t deserting Southern California but are said to be planning on keeping a smaller place in the Los Angeles area while becoming more bicoastal and possibly maintaining a residence in London as well.

The couple sold their Beverly Hills home for about $4.5 million to Al Checchi, co-chairman of Northwest Airlines, sources say. The house was listed in 1992 at just under $7 million. It was most recently listed with Barbara Duskin of Douglas Properties, Beverly Hills.

Built in 1927, the Italian Mediterranean-style home has four bedrooms and a maid’s apartment in nearly 8,500 square feet. The home is on 1.1 acres, with flower gardens, a pool, courtyard and fountain.

The Poitiers bought a $2.5-million co-op in Manhattan. The two-story, 5,500-square-foot unit is in a high rise on Fifth Avenue.

The New Jersey home of late PRESIDENT RICHARD M. NIXON has been put on the market at $1.2 million.

The nation’s 37th President succumbed to a stroke at a New York hospital April 22, four days after he was taken there by ambulance from his townhouse in Park Ridge, N.J., about 15 miles from Manhattan.

The townhouse had been Nixon’s residence since the spring of 1990, when he and former First Lady Pat moved there from a 15-room house nearby that they sold for $2.4 million, sources say. Pat Nixon died a year ago June 22.

The couple’s four-story, 3,500-square-foot townhouse has an elevator and nine rooms, including three bedrooms, a solarium opening onto a terrace; a breakfast room; sitting room with a cathedral ceiling, and library with three dormers and handcrafted bookshelves. The library may be re-created as a room at the Richard Nixon Library & Birthplace in Yorba Linda, sources say.

Mary Lenk of Lenk Friedberg Properties in Cresskill, N.J., has the listing.

Actors LIAM NEESON (“Schindler’s List”) and NATASHA RICHARDSON (TNT’s “Zelda,” about F. Scott Fitzgerald’s wife) have purchased what has been described as “a charming, Colonial-style country house” in Millbrook, Upstate New York, for close to its asking price of $1.25 million, sources say.

The five-bedroom, 5,000-square-foot home also has been called “a gracious farmhouse,” built in 1810.

Neeson, who also has a loft in Manhattan, sold his Los Angeles home in January for close to its asking price of $439,000.

Richardson, daughter of director Tony Richardson and actress Vanessa Redgrave, and Neeson, who was nominated for the best-actor Oscar this year, became interested in each other while co-starring in “Anna Christie” on Broadway in early 1993.

Sotheby’s International Realty handled the Millbrook transaction.

PRETTY PENNY, home of the late actress HELEN HAYES, is on the market at $1.5 million.

Hayes, the diminutive grande dame of American theater who had won two Oscars (most recently for “Airport” in 1970), lived at the residence in Nyack, N.Y., a suburb of New York City, for nearly 60 years. She was 92 when she died at a local hospital in March, 1993.

Her son, actor James MacArthur, and his wife, H.B., live in Palm Desert, Calif., but they are spending a lot of time at Pretty Penny until it is sold, sources say.

MacArthur grew up at Pretty Penny, where his mother and father, late journalist-playwright Charles MacArthur, entertained such theater legends as Laurence Olivier, Vivien Leigh and Noel Coward.

Pretty Penny is an 18-room, 5,000-square-foot Victorian, built about 1880 on the west bank of the Hudson River. It has terraced grounds and brick paths that wind through a formal rose garden past a fountain with a lily pond to a 60-foot-long pool.

Tom Anderson of Sotheby’s in New York City has the listing.