Used as a crosslinking agent in polymer chemistry, particularly in the production of ion-exchange resins and functional polymers. It enables the introduction of reactive sites by linking polymer chains through its two chloromethyl groups. Commonly employed in the modification of polystyrene and other aromatic-containing polymers to enhance mechanical and thermal stability. Also serves as a key intermediate in the synthesis of macrocyclic ligands, crown ethers, and chelating agents. Its bifunctional reactivity makes it valuable in organic synthesis for building complex molecular architectures.