When Donna Massey and her fiancé were on their way to a wedding at the Angel Orensanz Foundation on Norfolk Street last summer, they walked by the building a few times, thinking, “This can’t possibly be the place.”

Situated below Houston Street on the Lower East Side, the building appeared run down, its red and pink façade obscured by a tattered canopy.

After they went inside, “We were just wowed. We had never seen anything like it before,” Ms. Massey, 28, said. They soon decided to hold their wedding at the increasingly popular venue.

The nonprofit Angel Orensanz Foundation, which is run by brothers Angel and Al Orensanz, has booked 150 events so far this year, including 50 weddings, 80 bar and bat mitzvahs, and various cultural events. In comparison, five years ago it held just 75 events.

The space, at 172 Norfolk St., is New York’s only surviving structure built specifically as a synagogue. It was designed by architect Alexander Saeltzer and built in 1849 by German Jewish immigrants who lived in the neighborhood. The Reform congregation of Anshe Chesed (the People of Loving Kindness) opened its doors in May 1850.

By 1881, wealthier German Jews had moved uptown, and poor Jewish immigrants from Eastern Europe began pouring into the neighborhood. The synagogue fell on hard times, closing for long stretches and passing from one congregation to another until the end of World War I.

In 1920, the Orthodox congregation of Anche Slonin opened at the site. It maintained the building until 1974, when the aging congregation struggled to pay for the building’s upkeep and closed.

When the Orensanz brothers bought the building for $500,000 in 1987, it was home to squatters, vandals, and garbage. It took a year to clean the space, Al Orensanz said. The 62-year-old, who has a Ph.D. in sociology, dubs himself the building’s philosopher-in-residence. He runs the nonprofit with Angel, 60, an artist who is currently in Palermo, Italy, for a show of his drawings and sculpture.

When the Orensanz brothers, who are of Spanish Sephardic Jewish descent, acquired the site, they decided not to change the look of the building. Instead, they made functional upgrades, including installing theatrical lighting. The lighting system can project stars onto the 51-foot, blue cathedral ceiling, or drape almost any color over the pointed arch windows that feature design elements of the Cologne Cathedral.

“The building’s neo-Gothic architecture is dramatically highlighted with the use of theatrical lighting,” an event designer for Diana Gould who is helping plan Ms. Massey’s wedding, Ali Barone, said. For Ms. Massey’s ceremony, the walls will be covered in cool blue light, and the space will be filled with glowing pillar candles set on iron stands.

Despite the improvements, the unassuming façade, chipping paint, and creaky wooden floorboards might give some guests pause. “We are hoping that the majority of them will see the beauty that we see in it and remember our wedding for a long time to come,” Ms. Massey said.

“I like the history of it; I like that it’s not perfect, a little rundown,” the creative director of Lucky magazine, Andrea Linett, said. Ms. Linett, 42, is planning her wedding to freelance photographer Michael Waring, 36, later this month at the space.

In addition to being a popular venue for a slew of events, the building is also home to the Reform congregation the Shul of New York, which holds services on Friday nights and Saturdays, as well as Yom Kippur and other High Holidays.

The Angel Orensanz Foundation doesn’t charge the congregants for use of the space, and charges for weddings and other events according to a variety of factors, including the day of the week the event is held, the length of the event, and the number of guests. Ms. Massey is renting the space for her Saturday evening ceremony and reception at a cost of $16,000. Those renting out the building for an event are expected to bring everything themselves, including caterers, musicians, and decorations.

Next month, TRACES, an avant garde concert that begins before the audience arrives and continues after it leaves, will debut at the space. The artistic director and founder of Sympho, the company producing TRACES, Paul Haas, is holding the event there because of the acoustics, as well as a feeling of comfort the space provides. “It is one of the few venues in the world that thrills me while simultaneously giving me the sense of being at home,” he said.

The Orensanz brothers have made the space “an important cultural institution,” Joyce Mendelsohn, who is currently revising her 2001 book “The Lower East Side Remembered & Revisited,” said. The brothers “anchored the neighborhood in that they saved this building and it became a landmark.”