Derivatives of p-dimethylamino group substituted tetraphenylcyclopentadien- ones have been synthesized, condensing benzil or p-dimethylamino group substituted benzil and dibenzylketone or p-dimethylamino group substituted dibenzylketone. A new method has been found to synthesize p-dimethylamino group substituted benzil. p-Dimethylamino group substituted dibenzylketone and its intermediate compounds have been synthesized.