Used primarily as a reagent in analytical chemistry, it is widely employed in the colorimetric determination of nitrites. When combined with sulfanilic acid, it forms a diazo compound that reacts to produce a reddish-purple azo dye, which can be measured spectrophotometrically to quantify nitrite concentrations in water, food, and biological samples. This method is crucial for monitoring environmental pollution and ensuring food safety. Additionally, it serves as a coupling agent in various chemical syntheses, particularly in the production of dyes and pigments. Its stability and reactivity make it a valuable component in laboratory research and industrial applications.