4'-Aminoazobenzene-4-sulphonic acid is primarily used as an intermediate in the synthesis of dyes and pigments, particularly in the textile industry. It plays a crucial role in producing vibrant and long-lasting colors for fabrics. Additionally, this compound is utilized in the development of pH indicators due to its ability to change color in response to varying pH levels. It also finds applications in analytical chemistry as a reagent for detecting specific chemical substances. Furthermore, it is employed in research laboratories for studying azo compounds and their properties.