An efficient process for the synthesis of tetrahydrobenzo[b]pyrans derivatives was attained via the reaction of dimedone, various aldehydes and malononnitrile using [4,4′-Bipyridine]-1,1′-diium tricyanomethanide {[4,4′- BPyH][C(CN)3]2} as a green mild nano structure molten salt catalyst under solvent-free conditions at room temperature. To further investigation on catalytic properties of {[4,4′-BPyH][C(CN)3]2}, itwas used in the synthesis of amido and aminoalkyl naphthol derivatives under solvent-free conditions at 75 °C. {[4,4′-BPyH][C(CN)3]2} has advantages such as cleaner reaction profile, benign characters, cost effectiveness, reusability of the catalysts and being in agreement with the green chemistry protocols
