3-Nitrotetrazolium blue (chloride) serves as a versatile dye with numerous applications in both scientific and industrial sectors. This compound is pivotal in biological experiments for observing and analyzing cell structures, tracking biomolecules, evaluating cell functions, distinguishing cell types, detecting biomolecules, studying tissue pathology, and monitoring microorganisms. Its use spans from basic research to various diagnostic procedures in clinical settings. Additionally, it holds significant value in traditional industries like textile dyeing and in novel areas including functional textile processing, food pigments, and dye-sensitized solar cells.