Multicomponent one-pot synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-ones were achieved by the condensation of β-naphthol, aromatic aldehydes and cyclic 1,3-dicarbonyl compounds under neat conditions employing an efficient and eco-friendly Brønsted acidic ionic liquid (4-sulfobutyl)tris(4-sulfophenyl)phosphonium hydrogen sulphate as catalyst. The reaction work-up is very simple and catalyst can be easily separated from the reaction mixture and reused at least five additional times without any noticeable decrease in catalytic activity.