2,2‑Diphenyl‑1‑Picrylhydrazyl (DPPH) is a dark violet crystalline free radical compound, known for its use in antioxidant testing. With the formula C₁₈H₁₂N₅O₆ and CAS No. 1898‑66‑4, it offers ≥95% purity and strong colorimetric properties. It is widely used in research, EPR calibration, and food testing laboratories.