A novel inexpensive, efficient, environmentally-benign, and magnetically recoverable nanomaterial consisting of dihydrogen phosphate ions supported on silica-coated magnetite nanoparticle was prepared. The synthesized nanomaterial was characterized with FT-IR, XRD, FE-SEM, TEM, ICP and VSM. The obtained nanomaterial performed as a heterogeneous catalyst in the fast and convenient synthesis of tetrahydrobenzo[b]pyran derivatives under mild and solvent-free conditions. The optimal conditions for the preparation of tetrahydrobenzo[b]pyrans have been evaluated. Finest yield (88%) were obtained in the presence of 0.03 g of H2PO4-SCMNPs at 60 degrees C after 15 min under solvent-free condition. Furthermore, the nanomaterial displayed striking reusability in the titled catalytic reaction. Compared with the various previously reported catalysts, the newly synthesized nanocatalyst found to be most efficient with regard to operation simplicity, reaction time and yield. (c) 2017 Elsevier B.V. All rights reserved.