Pop superstar Madonna is suing the co-operative board at her New York building, claiming it wrongly banned her from buying a neighbouring apartment. The Material Girl tried to buy the home of Julie Clark Thayer to add to the pad she already boasts in the upscale Upper West Side block. But the co-op board blocked the move and the singer is now seeking a court order to force the sale to go through. She is also looking for legal fees and expenses from the board.