The synthesis of novel benzimidazole derivatives with varied carbon chain length was achieved via "one-pot" nitro reductive cyclization (6a-o). In each case, compounds were determined by the elemental analyses, FT-IR, mass, H-1 and C-13 NMR spectroscopy. Further, these derivatives were screened for their in vitro anticancer, in vitro and in vivo anti-inflammatory activities. The results revealed that the length of the carbon chain greatly affects the activity. Among the 15 derivatives, compound 6d induced maximum cell death in HeLa and A549 cell lines and compound 6a emerged as a potent anti-inflammatory agent. Also, the physicochemical properties of potent compounds were studied.