4-Iodotoluene is primarily used as an intermediate in organic synthesis, particularly in the production of pharmaceuticals and agrochemicals. It serves as a building block for the introduction of the tolyl group into various compounds, enabling the creation of complex molecules. Additionally, it is employed in cross-coupling reactions, such as the Suzuki and Heck reactions, which are essential for forming carbon-carbon bonds in the synthesis of fine chemicals. Its iodine atom can also be substituted or further modified, making it a versatile reagent in the development of dyes, pigments, and other specialty chemicals.