Keeping the objective to build up a new structural class of potent antimicrobials, a series of some new 4-Benzimidazol-2-yl tetrazolo[1,5-a]quinoline derivatives has been synthesized by reaction of tetrazolo[1,5 a]quinoline-4-carbaldehyde and o-phenylenediamine in the presence of an organocatalyst p-TsOH under the influence of microwave irradiation. The identity of all the compounds has been established by 1 H NMR, 13C NMR, FTIR, and elemental analysis. The synthesized compounds were subjected to in vitro antimicrobial screening against a representative panel of pathogenic strains including three Gram-positive bacteria (Bacillus subtilis, Clostridium tetani, and Streptococcus pneumoniae) and three Gramnegative bacteria (Escherichia coli, Salmonella typhi, and Vibrio cholerae) as well as two fungal organisms (Aspergillus fumigatus and Candida albicans) by employing broth microdilution method. Of the compounds studied, compound 5e demonstrated significant activity against a Grampositive bacteria Bacillus subtilis.