This research work deals with the synthesis of substituted tetrahydrochromenes and pyrazolo[3,4-b]-4H-pyrenesby the dehydration of the adducts formed by the tandem Knoevenagel–Michael reaction of aromatic aldehydes with 1,3-dicarbonílic compounds and analogous as 1-fenil-3-metil-2- pirazolin-5-ona,benzaldehyde derivatives and active methylene compounds as dimedone, ethyl cyanoacetate and ethyl acetoacetate interact by a Knoevenagel reaction in ethanolusing piperidine as catalyst to produce ethylenic derivatives. In the Michael addition, the ethylenic derivatives react with 1-fenil-3-metil-2- pirazolin-5-ona, to produce intermediate adducts that by dehydration, in the presence of hydrochloricacid, yield the final products. The reaction was monitored by thin layer chromatography (TLC). Tetrahydrochromenes and pyrazolo[3,4-b]-4H-pyranes were obtained in acceptable yields (35-78%),with me...