CLEVELAND, Ohio - Developer Robert Stark promised the city's planning commission that his proposed nuCLEus development downtown would provide "brand new iconic architecture that lets the world know we are competing at the highest level in global economy."

Stark didn't give specifics in the meeting, but said in an interview afterwards that he's negotiating with the Columbus office of NBBJ to hire two architects he considered the best in the international firm.

He declined to name the architects, but he said he'd like to combine NBBJ with Bialosky + Partners Architects of Cleveland, which has designed local projects including Stark's Crocker Park development in Westlake.

Jack Bialosky Jr., a principal of the firm, serves on the city's Downtown/Flats Design Review Committee.

Stark said he plans to announce the choice of architects "within a week," and that his Stark Enterprises and J-Dek Investments Ltd., of Solon, the firm partnering in the $250 million to $350 million downtown development, plan to be back at City Hall within six to eight weeks with conceptual designs for the large development.

On Friday, the planning commission voted 6-0 to approve an early diagrammatic plan for nuCLEus and a proposal for tax increment financing in which the city would allow the non-school portion of increased real estate tax revenue from the project to help finance project debt.

The project, to be located on two blocks south of Prospect Avenue and north of Huron Road east of East 4th Street, will include 120,000 to 140,000 square feet of retail, a 150- to 200-room hotel, 200,000 square feet of office space, 500 residential units and 1,500 to 1,600 parking spaces in garage levels stacked above street-level restaurants and stores.

On the way toward formulating a design team, Stark said he interviewed three of the hottest firms in the U.S. and the world – Studio Gang Architects of Chicago; BIG of New York and Copenhagen; and SHoP Architects of New York.

But he said the firms were in such heavy demand that they were unable to move as quickly on the Cleveland project as he and J-Dek wanted.

Stark said that speed is essential on nuCLEus in order to make the project's financing work.

"The great thing was that they all recognized how spectacular the [nuCLEus] development is," Stark said of the firms he and J-Dek considered.

But he said he also learned that architects whose work is in global demand could be choosy about their clients, which reverses the usual relationship in an interview.

"You don't get to pick them," Stark said. "When they're rock stars, they pick you. It was first time in my experience I was being interviewed. I had to sell the city, the time we're at in the city, and the importance of the city."

Stark said he was especially impressed with the Gang firm, headed by architect Jeanne Gang, who designed the 82-story Aqua residential tower near Grant Park in Chicago's Loop with undulating terraces that mimic waves.

But he said the firm couldn't provide a design team until the summer of 2015 for the Cleveland project.

Stark said the New York office of BIG also "turned my head," but he that the firm also couldn't meet his schedule.

BIG, known for projects including a waste-to-energy plant in Copenhagen with a ski slope on the roof, couldn't provide designers from its New York office who could meet Stark's timetable, he said.

The firm then later offered and withdrew its Copenhagen office when that office became too busy on prior commitments, Stark said.

Stark next turned to NBBJ, which also responded to a request for proposals from Stark Enterprises and J-Dek. The credits of the Columbus office include the Cleveland Clinic's recently completed Sydell & Arnold Miller Pavilion on Euclid Avenue at East 93rd Street.

Stark said he's fully confident that NBBJ can meet the standards he wants to set.

"They have done this type of architecture around the world," he said.

During Friday's meeting, Stark displayed a slide of three unnamed contemporary urban towers with highly articulated glass skins as an example of the direction he'd like to pursue for nuCLEus.

One of the towers looked like a stack of blocks slightly offset from one another; another twisted as it rose, producing a subtle series of asymmetrical outcrops. The towers were distinctive, and unlike anything on the Cleveland skyline.

Stark reiterated that he wants a design team with proven experience in designing tall office and residential buildings – something that he said doesn't exist in Cleveland.

"I don't want to do this for the first time with somebody," he said.

But he said he also wants a local firm collaborating with a non-Cleveland design firm to provide a strong understanding of the city, and to give the local firm a chance to gain new experience.

"You can do architecture like you have seen in New York Chicago and other cities, and you can make an impact," he said. "It can be transformational. You can start a movement and be transformational in the city."