Used primarily as an analytical reagent for the determination of metal ions, especially in spectrophotometric analysis. It functions as a chromogenic agent, forming colored complexes with certain metals, which allows for their detection and quantification. Also employed as an intermediate in the synthesis of dyes and antioxidants. Its structure enables radical scavenging properties, making it useful in evaluating oxidative stability in organic materials. Additionally, it serves as a derivatizing agent in environmental testing to detect phenolic compounds.