An efficient synthesis of dihydro-4H-benzo[4,5]imidazo[2,1-b]pyrano[2,3-d]thiazole by a multicomponent route starting from 2-((1H-benzo[d]imidazol-2-yl)thio)-1-phenylethan-1-one, an aromatic aldehyde and malononitrile is described. This protocol features a metal free approach with good substrate scope and decent yield. The heterocyclic skeleton obtained in this study may have interesting biological properties.
![Graphical abstract: A facile one pot synthesis of thiazolo[3,2-a]benzimidazole and pyran fused polyheterocyclic scaffolds](http://hg.y866.cn/compound/lib/scimg/usr/1/C9OB00300B.jpg)