AimAiming to produce pyridine azo disperse dyes with good fastness properties and promising antimicrobial activity, a number of novel systems of polyfunctionalized pyridine azo dyes and their selenium nanoparticles (SeNPs) were synthesized.Materials and methodsThe synthesized products were formed by the reaction of diazotized aniline derivatives or diazotized amino antipyrene with any of dibenzoyl methane or benzoyl acetone and cyanoacetamide in boiling ethanolic sodium ethoxide. The structures of the newly synthesized compounds were elucidated by elemental analysis and spectral data. Moreover, (SeNPs) of the pyridine azo disperse dyes were characterized by Ultra-Violet -Visible spectrophotometry, dynamic light scattering , X-ray diffraction, and transmission electron microscope analysis. On the other hand, the synthesized dyes and its (SeNPs) were applied for disperse dyeing of nylon 66 and their fastness properties were measured, such as washing, rubbing, perspiration, and light fastness. In addition, the antimicrobial activities for all the synthesized compounds and for (SeNPs) prepared compounds (2bN, 2cN, 2fN, 2gN, 2hN) were evaluated.ResultsCompounds 2bN, 2c, 2cN, 2fN, 2gN, 2h, 2hN, and 2i were the most active compounds against all Gram-positive and Gram-negative bacterial species. While, compounds 2b, 2f, 2g, and 5b were the most active toward some of the bacterial strains (at least two from the selected four strains). Moreover, compounds 2bN, 2cN, 2fN, 2gN, 2h, 2hN showed higher activity toward the fungal strain. Also, the minimal inhibitory concentrations for all the most active compounds were determined.ConclusionFinally, all the (SeNPs) compounds revealed higher activity against bacterial and fungal strains than the other synthesized compounds.