The Gateway complex had its genesis in the early 1980s.
By contrast, the vacancy rate for Newark's Penn Station area, which includes the Gateway complex, is now about 6 percent.
It joins the Gateway complex, with its baseball stadium and arena completed last year, as the city's newest attractions.
The Gateway complex was built on parking lots on the site of a former produce market.
Mr. Witkoff is under contract to buy the other three buildings totaling 1.26 million square feet at the Gateway complex.
By the 1980's a wave of renewal helped create a swath of glass-walled office towers, including the Gateway complex.
The agency said it had leases pending for 180,000 square feet at the Gateway complex.
The group has three sites in mind for an arena, with its top choice being on Market Street, near the Gateway complex.
Enter Gateway complex and go to Gateway One.
There are 11 of them, out of a total 27 residential buildings, counting the six-building Gateway complex as one building.