Ortho-dichlorobenzene (o-DCB) is a chemical compound with the formula C6H4Cl2. It consists of a benzene ring with two chlorine atoms attached to adjacent carbon atoms. This colorless liquid has a sweet, aromatic odor and is primarily used as a solvent in various industrial applications, including the production of dyes and pesticides. In addition to its industrial uses, ortho-dichlorobenzene is also found in some household products, such as air fresheners and mothballs. However, it is important to handle this compound with care, as it can be harmful if inhaled or ingested, and may pose environmental risks.