5-Aryl-3-oxo-δ-lactones (6-aryl-dihydro-2H-pyran-2,4(3H)-diones) can be prepared in high yields by the potassium carbonate promoted condensation of substituted benzaldehydes and ethyl actetoacetate in absolute ethanol. The presence of substituents, with varying electronic contribution, on the aromatic ring of the aldehyde is tolerated by these conditions. Results from a study on the use of various substituted benzaldehydes and ketoesters for the preparation of 5-aryl-3-oxo-δ-lactones, a class of compounds which exhibit a wide variety of biological activities, will be presented.