3-Nitrotetrazolium blue chloride is an isomer of p-Nitroblue Tetrazolium Chloride (sc-296003). Both compounds have commonly been used as a substrate in enzymatic assays. The compoud has been used to detect superoxide radical scavenging activity of a polyherbal formulation. The Notrobenzene blue chorides have also been utilized to observe in vitro formazan deposit formation in epidermal cells that had undergone ultraviolet light irradiation.