Abstract This paper describes the synthesis of a new series of 7‐amino‐5‐aryl‐6‐cyano‐5,8‐dihydropyrido‐[2,3‐ d ]pyrimidin‐4(3 H )‐ones 3 from the reaction of 6‐amino‐4‐pyrimidinones 1 with arylidene derivatives of malonodinitrile 2 . The structure of the final compounds was determined on the basis of nmr measurements, especially by 1 H, 1 H‐, 1 H, 13 C COSY, DEPT, HMBC and HMQC experiments.