Iodonitrotetrazolium chloride is widely used in biochemical assays as a redox indicator. It is particularly valuable in cell viability tests, where it helps to assess the metabolic activity of cells. When reduced by living cells, it changes from a colorless compound to a formazan dye, which is red or purple, providing a visual or spectrophotometric means to quantify cell health. Additionally, it is employed in microbiology to differentiate between metabolically active and inactive microorganisms, aiding in the study of microbial growth and survival under various conditions. Its application extends to plant physiology, where it is used to study seed viability and root activity, offering insights into plant health and development.