A series of monoazo disperse dyes based on 2-amino-5-mercapto-1,3,4-thiadiazole was prepared by coupling with various N-arylmaleimides. The dyeing performance of these dyes was assessed on nylon fabric. The dyes were found to give yellow to brown colour shades on dyeing with good depth and levelness on nylon fabric. The dyebath exhaustion, fixation and fastness properties of the dyes were also determined. The dyed fabric showed moderate to good light fastness and very good to excellent fastness to washing, rubbing, perspiration and sublimation. The IR and visible range spectral properties of the dyes were also determined.