A common strategy to incorporate four-membered ring system between benzimidazole and quinoline cores was developed by one-pot protocol involving the condensation of o-phenylenediamine with 2-chloroquinoline-3-carbaldehyde derivatives followed by intramolecular palladium catalyzed C-N coupling. A series of ligands, palladium sources, bases and solvents were screened to optimize the reaction conditions for the synthesis of quinoline-fused azeto[1,2-a]benzimidazoles. An efficient catalytic system for the introduction of 4-membered-ring system between benzimidazole and quinoline cores has been developed by one-pot intramolecular C-N coupling of o-phenylenediamine with 6-substituted-2-chloroquinoline-3-carbaldehydes.