Using nitrosyl chloride reagent, supported by nano silica gel, some of the azo dyestuffs, based on α-naphthol and β-naphthol, was synthesized in a very short time at room temperature, with high efficiency, which reduced the corrosion of the pot, environmental pollutionand the other problems. The molecular structure of the synthesized dyestuffs was characterized by FTIR, 1HNMR, 13C-NMR and UV-Vis spectroscopic techniques.The results showed that the structure of the synthesized dyestuffs corresponded with the general structure of the dye azo, and the applications are categorized into disperse or acidic dyes. The synthesized dyestuffs were applied to dyeing nylon and polyester, as we explored the ability of dyeing. Also, according to the results obtained in washing stability, nylon and polyester fibers are equal in b and c , respectively, and are higher than other washing fastness measurement modes. In general, the Light fastness of polyester fibers is slightly better compared to nylon fibers and its washing stability is lower. Finally, results indicated that the new method had a good ability for producing the azo dyestuffs. پرونده مقاله