Used primarily as an intermediate in the synthesis of dyes, pesticides, and pharmaceuticals. It serves as a building block for the production of certain herbicides and antimicrobial agents. Also employed in the manufacture of phenolphthalein and other triphenylmethane dyes. Its derivatives are found in some disinfectants and antiseptics due to their biocidal properties. Additionally, it is used in analytical chemistry as a reagent for detecting oxidizing agents and in the development of colorimetric tests for enzymes and peroxides.