Developers who built Plano's $3 billion Legacy West project are eyeing a vacant corner of downtown Dallas for a major mixed-use project.

Builder KDC has teamed up with landowner Hoque Global to plan the more than 20-acre skyscraper campus on the south side of downtown.

Located between Dallas City Hall and Interstate 30, the eight-block urban project would include office towers, retail and hotel space. It's one of the largest developments ever proposed for downtown.

Award-winning international architect Pelli Clarke Pelli designed the dramatic campus.

The largest building in the Dallas Smart District would be a 78-story skyscraper that would be the tallest in Dallas. (Pelli Clarke Pelli)

The centerpiece of the project is an office skyscraper that would be the tallest building in Dallas.

"It's a Legacy West type of project with the potential of 8 million square feet," said KDC chief executive Steve Van Amburgh. "We've been working on this for almost a year now.

"There are a lot of big companies that are circling Dallas-Fort Worth," he said. "Dallas needs to have a site that is large enough to accommodate a large employer."

Called Dallas Smart District, the planned urban development would stretch along Canton Street from the Farmers Market to the convention center.

The first phase would include 600,000 to 1 million square feet of office space, an urban grocery store, a food hall, a boutique hotel and green space.

Dallas businessman Mike Hoque has spent the last 36 months buying up and optioning blocks of parking lots and old buildings in that area of the central business district. He hired the architects to come up with a land plan.

"This is right downtown within walking distance of the center of the city," Hoque said. "We learned from Victory Park and everybody else about what should be built here."

Hoque said he chose Pelli Clarke Pelli because of its recent work on Uptown's new McKinney & Olive tower and its international reputation for top design work. Architect Gregg Jones, who did the McKinney & Olive tower, did the concepts for Dallas Smart District.

"The Dallas Smart District represents a special and unique opportunity for Dallas and greater Texas," Jones said in a prepared statement. "It is rare for a first-tier American metropolitan area to have this amount of contiguous developable land and building rights, all located in the heart of the city adjacent from the City Hall and convention center."

Pelli Clarke Pelli's designs show more than a half dozen high-rise buildings connected by green space and pedestrian walkways.

A parking lot behind City Hall would be repurposed as a central park.

78 floors

The tallest building envisioned for Dallas Smart District would be 78 floors, or about 200 feet higher than Bank of America Plaza, currently downtown's tallest building.

"It has fantastic access and close to all the amenities downtown," said KDC executive vice president Walt Mountford. "We are 18 miles from one of the busiest airports in the world."

KDC officials say they included the Dallas Smart District site in potential locations offered for digital retailer Amazon's new $5 billion second corporate headquarters complex.

It's one of more than three dozen properties being offered to the Seattle-based retailer for its campus, which could ultimately house 50,000 workers.

Hoque and his Dallas-based firm own a number of popular Dallas restaurants, and he is redeveloping the historic Adolphus Tower on Main Street.

Dallas Mayor Mike Rawlings said that Hoque and the Dallas Smart District designers "have put together an incredible vision that is sure to draw the attention of corporations, new residents and tourists, further elevating Dallas on the international stage."

While KDC is best known for its successful suburban corporate office projects, the developer is also a partner in the mixed-use Epic complex under construction on the east side of downtown Dallas.

"We've looked for an opportunity like this in Dallas for years, and there hasn't been a parcel of land large enough," said KDC president Toby Grove. "This is totally a blank canvas."

KDC teamed up with developers Karahan Cos. and Columbus Realty to build the 250-acre Legacy West project in Plano, which is the new home for Toyota's North American headquarters. It's the largest such development ever built in North Texas.

And KDC is building the $1.5 billion CityLine complex in Richardson that houses State Farm Insurance's regional office campus.

The Dallas Smart District has the potential for just as much construction.

Filling in the blanks

Economic development officials are eager to see the project move ahead, lighting up a dark corner of downtown.

"The Dallas Smart District development is situated in an exciting location at an exciting time for downtown Dallas," Kourtny Garrett, president and CEO of Downtown Dallas Inc., said in a prepared statement.

"Sitting in the southern area of downtown, the sites will feed off of the energy of projects like the AT&T Discovery District and Dallas Farmers Market, and will contribute to the efforts to better connect to the central core of downtown with the Cedars.

"The Smart District intent is also well aligned with our goals for the integration of technology, talent recruitment and overall innovative thinking for the future of downtown Dallas."