4-Methoxybenzylzinc chloride is primarily used in organic synthesis as a reagent for introducing the 4-methoxybenzyl group into various molecules. It is particularly valuable in cross-coupling reactions, such as Negishi coupling, where it facilitates the formation of carbon-carbon bonds. This compound is often employed in the synthesis of complex organic molecules, including pharmaceuticals and fine chemicals, due to its ability to selectively transfer the 4-methoxybenzyl moiety. Its application is also seen in the preparation of intermediates for agrochemicals and materials science, where precise functionalization is required. The reagent is favored for its stability and efficiency in catalytic processes, making it a useful tool in modern synthetic chemistry.