2,2′,6,6′-Tetramethyl-4,4′-biphenol, commonly known as TMQ (or 2,2′,6,6′-Tetramethyl-1,1′-biphenyl-4,4′-diol), is an organic compound with the molecular formula C16H18O2. This white crystalline solid features a biphenyl core substituted with four methyl groups and two hydroxyl groups, which contribute to its stability and antioxidant properties. TMQ is widely used in various industrial applications due to its ability to inhibit oxidative degradation, making it valuable in enhancing the performance and longevity of materials and products exposed to heat and light.