In attempt to search for more potent antimicrobial agents, a series of 7-nitro-1-(piperidin-4-yl)-4,5-dihydro-[1,2,4]triazolo[4,3-a]quinoline-derived sulphonamides were synthesized. Their structures were established by elemental analyses, IR, and NMR (1H and13C) spectral data. The antibacterial activity of the obtained compounds was investigated against different Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Bacillus subtilis and Staphylococcus aureus) bacteria and antifungal activity against two fungal strains (Aspergillus niger and Aspergillus clavatus) using disk diffusion method at various concentrations (20, 40, 60, and 80 μg/mL). The study reveals that most of the title compounds showed significant antibacterial and fungal activity when compared with their respective standards streptomycin and griseofulvin. © 2015 HeteroCorporation