1,4-benzenediol, also known as hydroquinone, is an organic compound with the chemical formula C6H6O2. It consists of a benzene ring with two hydroxyl (–OH) groups positioned at the 1 and 4 carbon atoms. This structure classifies it as a diol, specifically a symmetrical one, and it is commonly used in various applications, including photography and as a reducing agent. In addition to its industrial uses, 1,4-benzenediol is also found in some cosmetic products due to its skin-lightening properties. However, its use is regulated in many countries due to potential health risks, including skin irritation and other adverse effects.