A new development project in University City could transform the Philadelphia skyline.

The renovation of the former Post Office building at 30th and Market streets, along with the construction of a parking garage adjacent to the building, aims to connect Penn and Center City Philadelphia.

The project is a partnership between Penn Facilities and Real Estate Services and Brandywine Realty Trust.

Both structures are expected to be completed by September, according to Penn’s Director of Real Estate Development Paul Sehnert.

According to FRES spokeswoman Jen Rizzi, the Post Office building will turn into an Internal Revenue Service facility that will bring 5,000 jobs to the University City area.

The garage building will house various retail establishments, according to Sehnert.

The project also includes the proposed construction of the Cira Centre South — two high-rise buildings to be built at 30th and Walnut streets and 30th and Chestnut streets.

The proposed tower on 30th and Walnut Streets is anticipated to be a “first class corporate office building,” Sehnert said.

The use of the tower on 30th and Chestnut Streets is still being debated. Sehnert said he anticipates it will be either a residential building or a hotel.

He added that design time for the towers will take “approximately 12 to 18 months,” and that there is “no way of knowing” when construction on the towers will start.

The garage and Postal Service renovation is valued at $350 million, while the cost of the two towers is “still unknown,” according to Anthony Rimikis, senior vice president of urban development at Brandywine Realty Trust.

The design for the IRS headquarters will be “exactly similar,” he said. “Most people won’t see a difference.”

“We want to maintain the historic facade,” Rimikis added.

Rimikis said the loading dock outside the former Post Office building will be converted into a dining place for IRS employees.

He anticipates the 900,000-square foot building to be fully occupied by mid-2011.

Regarding retail for the towers, Rimikis explained that construction for both high rises cannot begin until they are 75-percent pre-leased.

“Our goal is to attract tenants from outside the city,” he said, adding that Brandywine Realty Trust has already contacted tenants from New Jersey and New York.

Although the Cira Centre South is still in the design process, Rimikis said they are tentatively planning to have the same “glass-curtain wall system” as the “Cira One” building on 30th and Arch streets.

According to Rimikis, Iron Chef Jose Garces will open a restaurant in Cira One in “about four months.”

“The Cira One is an exemplary building,” Sehnert said. “The Cira Centre South has the same potential to be as iconic a building as Cira One.”

Director of Real Estate and Facilities Ed Datz said he expects the Cira Centre South to be enhanced by Penn Park, on 31st Street between Walnut and South streets. He said the development will be a “gateway coming from the east.”

“Our interest is the strength and vibrancy of the community, both Penn and the neighborhood,” Datz added.