The multicomponent synthesis of 4H-benzo[b]pyran, pyranopyrimidinone and polyhydroquinoline derivatives has been achieved using catalytic amounts of calcium hydrogen phosphate in aqueous medium as a green, inexpensive and environmentally benign media. The process is operationally simple and has good to excellent yields. Moreover, computational parameters of some products were obtained using density functional theory at the B3LYP/6-311??G(d,p) basis set and correlated to experimental results.