2,6-Dichlorophenolindophenol sodium hydrate (DCPIP) is a blue-colored redox dye commonly employed as an indicator for the determination of vitamin C (ascorbic acid) content. DCPIP undergoes a reduction reaction with vitamin C, during which it changes from a blue-colored oxidized state to a colorless reduced form, providing a simple visual assay for ascorbic acid. Beyond vitamin C determination, DCPIP is utilized in diverse research applications, including the evaluation of enzymatic activity of gold nanoparticles, the development of UVB-specific dosimeters, its role as an electron acceptor in histochemical staining techniques, and investigations of mitochondrial electron transport chain activity.