The Bronsted acidic imidazolium-based metal-free and halogen-free ionic liquid hydrogen sulfate was immobilized on nanoporous silica SBA-15. The structures of synthesized catalysts were investigated using different characterization techniques, including FT-IR, small angle XRD, SEM, TEM and TGA. The [MPIm][HSO4]@SBA-15 is used as an alternative to conventional catalysts in the Knoevenagel-Michael-cyclization processes for the synthesis of tetrahydrochromenes and hexahydroquinoline carboxylates via a multicomponent procedure. The reaction time is reduced drastically and the reaction is progressed in an environmentally friendly way. The immobilized catalyst can be recycled without substantial loss of activity after seven runs. (C) 2014 Elsevier B.V. All rights reserved.