Developer Parkway Corp. has acquired part of the parking lot beside historic Walnut Street Theatre, clearing the way for a potential new contribution to the east Center City skyline.

Parkway paid $7.5 million for the 13,650-square-foot property at 805-13 Walnut St. in June, according to property records filed with the city.

Combined with an adjacent Sansom Street-facing parcel already owned by Parkway and development rights secured from the theater, the developer can build a roughly 20-story tower at the site, assuming most of the footprint is covered with a building comprised of equally sized floors and no special bonuses are used, according to calculations based on records filed with the city.

That’s taller than most existing buildings in the surrounding area near Washington Square.

“What we want to build is something special,” Parkway president Robert Zuritsky said in an email Friday. “[It’s a] great site for office, medical office, maybe even lab space, and of course residential.”

The theater sold the property as part of its fund-raising efforts to pay for a planned expansion on a section of the Walnut Street parking lot adjacent to the playhouse that it did not sell to Parkway, Zuritsky said.

News of the sale to Parkway was first reported by the Philadelphia Business Journal.