β-Naphthylamine is primarily used in the synthesis of azo dyes and pigments due to its ability to form stable colored compounds when diazotized and coupled with aromatic amines or phenols. It serves as an important intermediate in the dye industry, especially for producing red and orange shades used in textiles, leather, and printing inks. It has also been employed in the production of certain antioxidants and rubber chemicals. Historically, it was used in the detection of nitrite ions in analytical chemistry through colorimetric methods. However, due to its high toxicity and carcinogenicity, many of its applications have been discontinued or replaced with safer alternatives in most industrialized countries. Its use is now highly restricted under various health and safety regulations.