The reaction of 6-aminopyrimidin-4-ones 1 with benzaldehydes 2 and β-aminocrotononitrile 3 or benzoylacetonitrile 4 under microwave irradiation in dry media yields the 6-cyano-5,8-dihydropyrido[2,3-d]-pyrimidinones 5a-t. The structure of the synthesized compounds was determined on the basis of nmr measurements, especially by 1H,1H−, 1H,13C COSY, DEPT and NOESY experiments. In contrast with other pyrido-[2,3-d]pyrimidine derivatives, these compounds did not show any antifungal in vitro activity up to 250 μg/mL.