Novel pyridobenzimidazole derivatives were synthesized and characterized using spectral techniques like IR, NMR, mass spectroscopy and elemental analysis. For the synthesis pyridobenzimidazole derivatives, 2’-amino-3’,5’-dicarbonitrile, 4’-methyl pyrido-[1,7-a]benzimidazole 1(a-b) treated with Carbon Disulphide (CS2) in aq. K2CO3 to afford dithiocarbamate intermediates which were further desulfurylized with 2,4,6-trichloro-1,3,5-triazine (TCT) to provide compounds 2(a-b) which on further condensation with benzoyl hydrazine hydrazide gave compounds 3(a-b) which was treated with both H2SO4 and NaOH to give compounds 4(a-b) and 6(a-b), respectively. 4(a-b) which refluxed with hydrazine hydrate formed 5(a-b) and 6(a-b) were reacted with methyl iodide to give compounds 7 (a-b). All synthesized derivatives screened against a series of reference strains of bacteria and fungi showed significant to moderate activity against tested bacterial strains whereas some compounds exhibited potent fungicidal activity.