In this work we describe a simple and rapid method for the synthesis of a series of pyrano[4,3-b]pyranderivatives by a three-component reaction between 4‑hydroxy-6-methylpyran-2-one, malononitrile and a variety of aromatic and heteroaromatic aldehydes. The reactions are carried out at reflux of a water/ethanol mixture in the presence of 10 mol% of pyridinium p-toluenesulfonate as catalyst with excellent