For arts organizations, progress at the World Trade Center site has so far resembled a Beckett play: waiting and disappointment, followed by more waiting and disappointment. Opposition from victims’ relatives and political fighting have meant that none of the dreamed-of cultural projects has broken ground. And now that the Lower Manhattan Development Corporation has been disbanded, arts groups are more worried than ever that the planned performing arts center and $7 million worth of federal arts grants will remain on paper.

So the official reopening on Sept. 22 of 3-Legged Dog’s performance space in the area known as the Liberty Zone is a bit like the opening of a general store in a frontier town: some concrete evidence of progress.

“I have a lot of faith in 3-Legged Dog; it’s the wave of the future,” said Tom Healy, president of the Lower Manhattan Cultural Council. Mr. Healy cited the company as much for its aesthetic daring as for its nontraditional business model. “When you’re talking about rebuilding downtown for the 21st century, the idea of an organization that is pushing boundaries of new media is really compelling,” he said.

An experimental multimedia and theater company, 3-Legged Dog was located at Fiterman Hall, next to 7 World Trade Center, before the 9/11 attack destroyed its space. Today the spot reflects the area’s uneven development: Fiterman (part of Borough of Manhattan Community College) is still shrouded in black netting and deserted, while in the lobby of the rebuilt 7 World Trade Center the artist Jenny Holzer has installed a text-scrawling video memorial, 65 feet wide and 14 feet high.

“On Sept. 11 in the afternoon everybody who was working with the company at that time came over to my place at 24th Street, and we decided to continue doing what we were doing to the best of our ability despite the attack,” Kevin Cunningham, the executive director of 3-Legged Dog, recalled.

The result is the new 3LD Art and Technology Center, a 12,500-square-foot warren of theaters and offices. The architect Thomas Lesser designed the $4.8 million center to fit within a concrete parking garage on Greenwich Street, near ground zero. Visitors to Mr. Cunningham’s small street-front office have an unusual sense of place; you can feel the passage of cars from the garage overhead, while the office’s full-length window makes you almost feel as if you were sitting on the sidewalk.

For the Sept. 22 opening, 3-Legged Dog has planned a gala with performances by a number of the city’s best-known avant-garde companies, including Radiohole and Collapsable Giraffe.

Mr. Cunningham said that after 9/11 he began working to find a new home. In 2002 Denham Wolf, a real estate company specializing in nonprofit deals, found the Greenwich Street space. A $225,000 development loan from the Elizabeth Steinway Chapin fund, administered by the Alliance of Resident Theaters, allowed 3-Legged Dog to hire what Mr. Cunningham calls “a really nasty junkyard-dog lawyer,” who helped the company secure a 20-year lease from the Metropolitan Transportation Authority, the garage owner, and hire an architect.

City Councilman Alan Jay Gerson, who represents District 1 in Lower Manhattan, also helped get $500,000 worth of free electronic and lighting equipment through the Department of Cultural Affairs.

Before 9/11 the company had largely financed its nonprofit art-making with a for-profit company that developed multimedia performance software; its clients included the Wooster Group and NEC Technologies. But after the attack investors in the software venture pulled out. To pay for the new center the company has been busily fund-raising.

“The experimental arts in New York are in dire jeopardy right now,” Mr. Cunningham said. The only other new cultural organization nearby (though not in the Liberty Zone itself) is Dance New Amsterdam’s expansive city-renovated space on Lower Broadway.

"What’s alarming is that if the experimental tradition dies in New York, where it’s been rampant since the 20’s, we’re going to lose our identity even more than we already have,’’ Mr. Cunningham said. “I’m not talking about the Disneyfication of Times Square. I’m talking about a core thing that brings new brains to the city.’’

He added: “We can’t do anything about the atrocious funding situation in this country, but we can do something about the basic cost structure of production. We can address the cost issues with smart business thinking, basically.”

So 3-Legged Dog rents out space to other groups, operating a bit like a cooperative. The rental fee includes the use of video and lighting equipment, as well as training sessions on how to use it and round-the-clock access to the space.

The New Georges company, for example, produced Sheila Callaghan’s “Dead City,” an updated Joycean fantasy, at the center in June (before its official opening); in August, the Here Arts Center’s American Living Room arts festival was held there while its own space in the South Village was being renovated.

“I think 3LD exemplifies a trend we see with Here and P.S. 122,” said Mary Harpster, the deputy director of the Alliance for Resident Theaters. “They’re all somewhat curated, have a resource space and have a point of view, and they’re not only doing their own work but supporting other emerging companies.”

Mr. Healy of the Lower Manhattan Cultural Council went further, seeing 3-Legged Dog as opening a window of cultural opportunity for Lower Manhattan.

“If as a city we thought about investing public dollars in a corridor of new explorations, incubators of new cultural activity, that’s a far wider investment than the $50 million that’s supposedly been put aside for a major concert hall,” he said. “What 3LD represents is a more organic way of making the arts part of rebuilding downtown.”