A series of imidazopyridine/imidazopyrimidine-benzimidazole conjugates (11a-t) were synthesized and evaluated for their antiproliferative activity. All these conjugates showed moderate to better cytotoxic activity against the human cervical (Hela), lung (A549), prostate (DU-145) and melanoma (B-16) cancer cell lines. Among them, conjugates 11i and 11p showed significant antiproliferative activity against lung cancer cell line A549 with IC50 values 1.48 and 1.92 µM respectively. Flow cytometric analysis revealed that these conjugates induced cell cycle arrest at G2 /M phase in A549 cell line leading to caspase-3 dependent apoptotic cell death. The tubulin polymerization assay (IC50 of 11i is 2.06 µM and 11p is 2.26 µM) and immuofluorescence analysis displayed that these conjugates effectively inhibit microtubule assembly at both molecular and cellular levels in A549 cells. Further, Hoechst staining, caspase 3 activation assay, DNA fragmentation analysis and Annexin V-FITC assay also suggested that these compounds induced cell death by apoptosis. Furthermore, molecular docking studies indicated that these conjugates interact and bind efficiently with tubulin protein. Overall, the present study demonstrates that the synthesis of imidazopyridine/imidazopyrimidine-benzimidazole conjugates as promising tubulin inhibitors with G2 /M phase cell cycle arrest and apoptotic-inducing ability.