Three series of tetrazolo[1,5-a]quinoline derivatives have been synthesized. The first series was synthesized starting by the condensation of tetrazolo[1,5-a]quinoline-4-carboxaldehyde 2 with substituted thiosemicarbazides, followed by cyclization of the resulting thiosemicarbazones 3 with malonic acid in the presence of acetyl chloride to give pyrimidyl derivatives 4a-c. The second series was prepared by the condensation of the latter compounds 4a-c with the selected aromatic aldehydes to afford the arylidene derivatives 5a-f. The third series 7a-c was synthesized by condensation of tetrazolo[1,5-a]quinoline-4-carboxaldehyde 2 with the appropriate acetophenone, followed by cyclocondensation of the formed alpha,beta-unsaturated ketones with thiourea. The newly synthesized compounds were evaluated for their anti-inflammatory and antimicrobial activities. Four compounds were proved to be as active as indomethacin in animal models of inflammation.