The present study deals with the synthesis of four different azo-azomethine derivatives; this is done by two steps; the first step is diazotization of sulfonamides (sulfanilamide, sulfacetamide, sulfamethoxazole, and sulfadiazine) separately, followed by the second step; the coupling reaction of diazotized compounds with isatin bis-Schiff base named 3-((4-nitrobenzylidene) hydrazono)indolin-2-one. The later one (bis-Schiff base) was synthesized by the reaction of 3-hydrazono-indolin-2-one with p-nitrobenzaldehyde. The chemical structures of newly synthesized compounds were approved on the basis of their FTIR, 1H-NMR, and CHNS elemental analysis data results. The synthesized azo compounds were tested in vitro for their antimicrobial potential using well diffusion method. All the target compounds were clearly inhibited Escherichia coli and Candida albicans, while only compounds 2b and 2c show antibacterial activity against Pseudomonas aeruginosa. The most active compound among the prepared azo compounds against Escherichia coli, Pseudomonas aeruginosa, and Candida albicans is compound 2b.
