The main aim of this paper is the synthesis of new azo nitroso-based disperse dyes with better dyeing properties on synthetic fibers. In this regard, bis-azo nitroso naphthalene dyes were synthesized via the diazo coupling reactions of 4-nitroaniline with 1-hydroxy-2-nitrosonapthalene. Products formed were characterized by 1H and 13C NMR. Absorption values in the UV-vis spectra of the derivatives under study were quite close and they exhibited multiple maxima in the 386 – 513nm range. The dyeing process, dye exhaustion on polyethylene terephthalate (PET) and polyamide 6 (nylon 6) fabrics, and the durability of the dyes on the textile substrates were evaluated. It was found that the light fastness ratings of the dyed fabrics could reach grade 6/7 to 7, washing fastness gave excellent values of grade 5 while rubbing and perspiration fastness grades were rated at 4/5 to 5 on the International Geometric Scale. The results obtained suggest that the dyes could be used as disperse dyes on synthetic polymers fibers.