Used primarily in hair dye formulations, it acts as a key intermediate in the production of oxidative hair colorants. It reacts with couplers in the presence of hydrogen peroxide to form a range of vibrant and long-lasting hair colors. Additionally, it is employed in analytical chemistry as a reagent for detecting trace amounts of chlorine in water, ensuring water safety and quality. Its application extends to the textile industry, where it is utilized in dyeing processes to achieve specific shades on fabrics.