Ortho-dichlorobenzene, often referred to as ODCB, is a chemical compound with the molecular formula C6H4Cl2. It is a colorless, highly volatile liquid with a sweet odor. Ortho-dichlorobenzene is primarily used as an intermediate in the synthesis of various chemicals and as a solvent in industrial applications.

One of its notable applications is in the production of pesticides, particularly insecticides and herbicides. It serves as a building block in the synthesis of these agrochemicals. Additionally, ortho-dichlorobenzene is employed in the manufacture of dyes and pigments, where it acts as a precursor in the production of specific dye intermediates. Its solvent properties make it useful for dissolving and formulating various products, such as paint thinners and paint removers. While ortho-dichlorobenzene is versatile and valuable in the chemical industry, it should be handled with care due to its toxicity and potential environmental impact.