Biphenyl is an organic compound consisting of two connected benzene rings. It is a colorless, crystalline solid with a distinct odor and is primarily used in the production of various chemicals, including polychlorinated biphenyls (PCBs). Biphenyl is also utilized as a heat transfer agent in industrial applications due to its thermal stability. In nature, biphenyl can be found in small amounts in coal tar and is produced during the combustion of organic materials. It is important to handle biphenyl with care, as it can be harmful if ingested or inhaled. Additionally, it is regulated due to its potential environmental impact.