Image courtesy of CBT Architects.

The new owners of a Back Bay parking lot are proposing a 5-story building to tap into the neighborhood’s high-rent office and retail markets.

L3 Capital of Chicago is seeking approval for a 43,500-square-foot building at 149-155 Newbury St., a one-third-acre lot that it acquired last July for $40 million.

In a project notification form to the Boston Planning & Development Agency, L3 Capital said no restaurant tenants will occupy the retail space on the first two floors. Zoning prohibits food service without a conditional use permit. No parking is required or proposed.

“With its prime positioning along the Dartmouth Street Corridor, the site serves as a landmark and gateway into the pedestrian friendly retail corridor of Newbury Street,” developers wrote in their submission.

Designs by Boston-based CBT Architects call for a masonry, metal and glass exterior.

Asking rents for class A office space in Back Bay averaged $82 per square foot at year’s end with a 2.5 percent vacancy rate, according to research released Wednesday by brokerage Newmark Knight Frank. In comparison, asking rents averaged $76.71 per square foot in the Seaport District and $74.91 in the downtown Financial District.

Members of the project team include general contractor Shawmut Design and Construction, structural engineer Thornton Tomasetti, civil engineer HSH, mechanical engineer Syska Hennessey and legal counsel Nixon Peabody LLP.