A convenient and efficient method for one-pot synthesis of 4H-chromene and 3,4-dihydropyrano[c]chromene derivatives by a multi-component condensation reaction of aromatic aldehydes, malononitrile and dimedone or 4-hydroxycoumarin in the presence of piperazine as a catalyst under solvent-free conditions has been developed. The features of this procedure were characterized by the following: good to high yields, one-pot procedure, short reaction time, and operational simplicity
