“…In general, 3,4‐dihydropyrano[3,2 c]chromenes are accessible through the one‐pot three‐component condensation of an aromatic aldehyde, malononitrile, and 4‐hydroxycoumarin. Several synthesis of these heterocyclic compounds have been reported, using various catalysts like synthetic diammonium hydrogen phosphate (DAHP), Tetrabutylammonium bromide (TBAB), Sodium dodecyl sulfate (SDS), 4‐(dimethylamino) pyridine (DMAP), [ 14 ] poly(N,N′‐dibromo‐N‐ethyl‐benzene‐1,3‐disulfonamide) [PBBS], ionic liquid [DBU][AC], [ 15 ] Silica‐Grafted Ionic Liquids[Sipim]HSO 4, starch solution, thiourea dioxide, poly (ethylene glycol) grafted N,N‐dimethylaminopyridine functionalized dicationic ionic liquid [DMAP‐PEG1000‐DIL][BF 4 ], 1‐Methylimidazolium tricyanomethanide ([HMIM]C(CN) 3 ) and Ru(II) complexes bearing tertiary phosphine ligands . Despite this, these procedures have drawbacks, which imply unsatisfactory yields, extended reaction times and the use of expensive catalysts.…”