This article originally appeared on The Real Deal Chicago

Convene is expanding its share of Chicago’s rapidly growing co-working market.

The New York-based firm, which offers on-demand corporate meeting and event space, will open a 45,000-square-foot flex office on the 14th and 15th floors of the Citadel Center at 131 South Dearborn Street, the company announced.

Convene opened its first Chicago location, a 50,000-square-foot suite with an in-house cafe, on the first two floors of Citadel Center in January.

The expansion makes three new co-working spaces among the four Chicago buildings where Convene plans to operate by 2020. The firm last year announced a deal with Sterling Bay to take almost 90,000 square feet in its renovated office building at 311 West Monroe Street, including more than 58,000 square feet of work space.

It will also fill an entire floor in Sterling Bay’s upcoming 19-story office tower at 333 North Green Street, about two-thirds of which will be flex office space. All told, Convene plans to claim about 160,000 square feet of co-working space by next year.

Convene will also take over the entire third floor of Willis Tower after the Blackstone Group completes its $668 million renovation next year. But all 90,000 square feet of its Willis Tower footprint will be dedicated to meetings and events, similar to its ground-floor digs at Citadel Center, with no workaday offices.

Ryan Simonetti and Chris Kelly co-founded Convene in 2009 to outfit office buildings with amenities and shared spaces that provide them with a “hospitality and services component,” Simonetti told The Real Deal in an interview earlier this year. Last year, Convene expanded to join the myriad companies opening co-working spaces in cities across the country.

But Simonetti doesn’t see his company as a direct competitor with WeWork, which is now Chicago’s largest co-working firm and one of its largest overall office tenants, he said. Convene’s work spaces are tailored to firms with about 50 or 60 employees, what Simonetti called the “missing middle” of office real estate.

“We see a huge gap in the market for companies that have graduated out of a co-working environment, but don’t feel like they can commit to a long-term lease in a traditional model,” Simonetti said.

WeWork announced in March it would break into Convene’s territory by opening a suite of event spaces across its Chicago locations.

The firm now counts 24 locations in six American cities, and Simonetti doesn’t expect its reach to stop growing, he said. Earlier this year, Kelly’s title shifted from president to vice chairman so he can focus on the company’s national profile while it scouts a new leader who can oversee international expansion, Simonetti said.

“We’re looking for someone at the president level who has operated a business at a very different scale than one were currently operating on,” Simonetti said. “We’re trying to scale as aggressively as our landlord companies and customers need us to.”

The company, though, said Friday the search for a new president is on hold for now.

Convene is set to open its co-working spaces in the Citadel Center and 311 West Monroe during the fourth quarter this year. Its space at 333 North Green is slated to open in 2020.