Two Mellon Center, better known to many as the Union Trust Building, is for sale.

No price has been set, but listing broker Jeffrey B. Ackerman of CB Richard Ellis said he expects the building to sell for close to the $30.8 million value assigned to it by Allegheny County for tax purposes.

The 11-story building's 601,000 square feet of office space, which includes two basement levels, has been vacant since the third quarter of 2006. The first floor's occupants include Larrimor's and a Citizens Bank branch.

Designed for Henry Clay Frick by famed architect Frederick J. Osterling, the Flemish Gothic building was completed in 1917. It originally served as the headquarters for the Union Trust Co., founded by the Mellon and Frick families, and contained four levels of retail shops. The Mellon family's banking operations merged with the Union Trust Co. in 1946 to form Mellon National Bank and Trust Co.

The DeBartolo family acquired the building for $8 million in 1987, performed a complete renovation, and leased it back to Mellon Bank for 20 years. In October, the DeBartolos granted a deed in lieu of foreclosure to the current owner, Teal Rock 501 Grant Street LP.