The structure of dihydro-1,3,5,5-tetramethyl-2-(1-phenylethylidene)-4,6(1H,5H)-pyrimidinedione (1) was determined by X-ray crystallography. The phenyl group made an angle of 62.2(1)° with the ethylidene group. The dihydropyrimidine ring adopts a boat conformation. An intermolecular C-H…O and π…π interaction was observed in the crystal lattice.
