The title compound 9-(4-hydroxybutyl)-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione was synthesized in 72% yield through a simple, convenient and environmentally friendly one-pot reaction between dimedone and 3,4-dihydro-2H-pyran in aqueous citric acid. Additionally, a plausible reaction mechanism for the formation of the target xanthene is proposed.