The owners of the Manning's/Denny's building, which was designated a Seattle landmark last month, have filed suit in King County Superior Court to officially challenge the action.

A development entity of The Benaroya Company, Mikie Ballard LLC, which owns the old diner and surrounding property, argue that landmark status prohibits them from making any money off their property.

The Seattle Landmarks Preservation Board voted 6-3 on Feb. 20 to designate the exterior of the old diner at 5501 15th Ave. N.W. a city landmark, which means it can't be torn down.

The lawsuit seeks to reverse the board's decision.

Benaroya is in negations to sell the property and building to Rhapsody Partners, a development firm that plans to build an eight-story condo there.

"The boarded up former Denny's is not an important historic or architectural building, nor the work of a significant architect," said Marc Nemirow, a senior executive for Benaroya for Benaroya. "The landmark board agreed with these conclusions, but incredulously decided to designate the building a landmark anyway. This action isn't legal."

The board voted to preserve the building because of its important spatial location and "it is an easily identifiable visual feature of its neighborhood or the city and contributes to the distinctive quality or identity of such neighborhood ..." according to one of the criteria used to determine landmark status.

Nemirow said that although the appeal was filed, the applicant continues to work through the process.

"Due to statutory deadlines, it was necessary to file the court appeal in response to the board's decision, but we continue to be focused on the ongoing administrative process."

The board must now negotiate with the landowner, Benaroya, regarding the economic implications of the landmark decision.

"We are concentrating our efforts on preparing information to assist the board in a proper evaluation of the economic impacts of its decision," Nemirow said.

Nemirow said that no timetable has yet been set for consideration of the appeal, and it is his desire to pursue the current process with the Landmarks Board. He hopes to avoid the need to pursue the court appeal.