The Pittsburgh Civic Design Coalition will hold a forum for Pittsburgh mayoral candidates at 6 p.m. Sept. 27 at the David L. Lawrence Convention Center, the group announced yesterday.

The coalition said both Mayor Luke Ravenstahl, a Democrat, and his Republican challenger, Mark DeSantis, have agreed to participate. The 90-minute event will focus on civic design, historic preservation, and spurring development, and will not be open to the general public. Some 5,000 architects, planners and civic leaders are being invited to attend.

WDUQ Radio personality Katherine Fink will moderate, and the event will be aired later on that station.

Mr. DeSantis has said that there should be eight debates leading up to the November election. Mr. Ravenstahl's campaign has agreed to debate, but has argued for fewer debates.