An efficient route for the synthesis of 5-(arylpropenylidine)-2,4,6-pyrimidinetrione 3 from an appropriate α,β-unsaturated aromatic aldehydes 1 and barbituric acid 2 under both non-catalytic and solvent-free microwave irradiation conditions was described. In this way, a range of biologically important compounds 3 was obtained in good to excellent yields (86-98 %) in a very short reaction time (30-80 s).