When architect Peter Zellner first unveiled his design for the new Matthew Marks Gallery in West Hollywood, it was met with enthusiasm from the planning department and the mayor. But the city has strict design guidelines on the books: New buildings must have windows and architectural detail. The gallery was, well, an “ice cube,” says Zellner, and Marks was in uncharted territory, choosing to make his West Coast debut in the scruffy neighborhood between La Brea and Fairfax Avenues rather than the established art scene in Culver City.

But Zellner was able to skirt the guidelines with the addition of Ellsworth Kelly’s 40-foot-long, 5,000-pound, rectangular, black metal minimalist sculpture to the gallery’s facade; now the entire building is considered a treasured piece of public art. “When the Kelly went on, it really felt like it was complete,” said Zellner, founder of the Los Angeles–based firm ZELLNERPLUS. “Last week the building seemed naked to me.” Far from feeling protective of his ego or output, the architect describes his afternoon discussing the design with Kelly, “the last standing modern master in the United States,” as “one of the best moments of my life.” Matthew Marks represents Kelly, 88, and he asked the artist for a contribution to his new outpost.

Kelly is no stranger to collaborations or contributing site-specific works to important buildings. His painted aluminum wall sculpture for Renzo Piano’s 2009 addition to the Art Institute of Chicago and a wall sculpture in the lobby of Tadao Ando’s 2001 Pulitzer Foundation for the Arts building in St. Louis are just two of many such commissions. In fact, his very first public commission and architectural collaboration, Sculpture for a Large Wall (1957), made the May 1957 cover of Architectural Record. This project originated when lighting designer Richard Kelly (no relation) commissioned Kelly to create a sculpture for the restaurant in Philadelphia’s then-new Penn Center Transportation Building, but when the building’s architect Vincent Kling saw the design, he requested the sculpture for the lobby instead. Sculpture for a Large Wall was the result. RECORD wrote about the building and chose a detail of the 64-foot-long artwork made of anodized aluminum panels for the cover.

Fast-forward to the late 1990s: Kelly learned that the Transportation Building had been sold. On a visit, he was alarmed at the condition of the building and his creation. “I said, ‘Oh, my god, I’m going to try and get this back. They’re going to destroy it,’” says Kelly. He arranged for its removal, and Marks displayed it in his New York gallery in 1998. That same year, Jo Carole and Ronald S. Lauder purchased Sculpture for a Large Wall and gave it to the Museum of Modern Art.

Speaking from his studio in Spencertown, New York, Kelly recalled looking intently at the model of Zellner’s Los Angeles gallery design and then having a “flash” of inspiration: “In my work I wait for these flashes.” He calls black and white the two “non-colors,” but guesses that of the 1,000 or so paintings he’s completed since 1949, a quarter of them have been black and white (about 50 were recently on display at the Haus der Kunst in Munich; the show will move to the Museum Wiesbaden in March). “It’s always been very important for me, black. It’s fundamental. It’s like the opposite of a shadow,” says Kelly. “If it was color [on the gallery] it would be too decorative for me.” Zellner likes that the black bar can be misinterpreted as signage.

The gallery facade evokes two of Kelly’s early works—a 1954 collage, Study for Black and White Panels, and a 1966 painting, Black Over White. “I’ve always wanted to design a building that doesn’t have a use,” says Kelly. “That’s probably a definition of sculpture.”

The Los Angeles Matthew Marks Gallery opened on January 19. Its inaugural show, Ellsworth Kelly: Los Angeles, runs through April 7, 2012, and includes six new two-panel paintings by the artist.