Used primarily as a stable free radical in scientific research to study antioxidant activity. It is commonly employed in the DPPH assay to measure the ability of compounds to scavenge free radicals, where the reaction causes a color change from purple to yellow, measurable by spectrophotometer, providing insights into their potential as antioxidants. This application is crucial in fields like food science, pharmaceuticals, cosmetics, and supplements, where understanding and enhancing antioxidant properties is essential for product development and health benefits. Additionally, it serves as a standard in electron paramagnetic resonance (EPR) spectroscopy for calibrating instruments and studying radical interactions. Its stability and distinct reactivity make it a valuable tool in chemical and biochemical research.