4-Chloro-2-iodobenzonitrile is primarily used as an intermediate in organic synthesis, particularly in the production of pharmaceuticals and agrochemicals. Its structure, featuring both chlorine and iodine substituents, makes it a versatile building block for constructing complex molecules. It is often employed in cross-coupling reactions, such as Suzuki or Sonogashira couplings, to introduce aromatic nitrile groups into target compounds. These reactions are crucial in developing active pharmaceutical ingredients (APIs) and other biologically active compounds. Additionally, its halogenated nature allows for further functionalization, enabling the creation of diverse chemical structures for research and industrial applications.