We have reported a one-pot two-step methodology for the synthesis of highly condensed heterocycles, pyrrolo[1,2-a][1,4]benzodiazepines, by a modified Pictet–Spengler reaction under mild conditions in a short time. Our approach has a few advantages over the conventional two components synthesis as it is step and atom economic, environmentally benign and a convergent synthetic method. We have discussed here the broad substrate scope of this novel methodology.