Abstract A new method is reported for the synthesis of 2-R-substituted [1] benzopyrano [4, 3- d] pyrimidin-5-ones (R= p-phenyl, p-chlorophenyl-, p-carbamoylphenyl-, 3-pyridinyl-, 4- pyridinyl-, 2-pyrazinyl-, pyrrolidino-, morpholino-, 3, 6-dimethyl-1-pyrazolyl-) by the reaction of 4-chloro-3-formylcoumarin with salts of the corresponding amidines RC (= NH) NH 2 HX in DMF in the presence of piperidine or triethylamine. 3-Formyl-4-coumarin and 2- ...