Philadelphia's Parkway Corp. and Nightengale Properties of New York are proposing a mixture of offices, shops and apartments on a 1.5-acre parcel that they own together on the northwest corner of Broad and Spring Garden Streets.

Planned are a tower with up to 500,000 square feet of offices and an apartment building with an as-yet undetermined number of rental units, Steven Gartner, who is marketing the property’s retail space as a managing director with commercial real estate firm CBRE, said in an interview Monday. Both buildings would rise atop a podium containing at least 50,000 square feet of stores and restaurants.

The site is currently used as a parking lot. Parkway and Nightengale are aiming to complete the project by late 2019, Gartner said.