Used primarily as a reagent in analytical chemistry for the detection and determination of various metal ions, particularly bismuth, lead, copper, and zinc, due to its ability to form colored complexes with these metals. In biological research, it serves as a staining agent to visualize certain cellular components under a microscope. Additionally, it finds application in the synthesis of organic compounds where its unique chemical properties facilitate specific reactions. In environmental science, it is employed to monitor and assess metal contamination in water and soil samples, providing crucial data for pollution control and remediation efforts.