Widely used as a chromogenic substrate in biochemical assays, particularly in antioxidant capacity measurements. It is a key component in the ABTS assay, where it is oxidized to form a stable blue-green radical that absorbs light at 734 nm. This color change allows for the quantification of antioxidant activity in various samples, including biological fluids, plant extracts, and food products. Due to its high sensitivity and reproducibility, it is favored in research and quality control for evaluating the radical scavenging potential of compounds. Also employed in enzyme-linked assays involving peroxidases and oxidases, where it acts as an electron donor, enabling detection through visible color development.