A new synthetic strategy for industrially important deep-shade disperse azo dyes was presented in this study. The key procedure is to prepare stable solid diazonium salts of weakly basic amines in the absence of concentrated sulfuric acid. Diazotization by tert-butyl nitrite in ethylacetate was allowed to proceed in the presence of equivalent 1,5-naphthalenedisulfonic acid as stabilizer of diazonium