Tetrabutylammonium Dibromoiodide is primarily utilized in organic synthesis as a phase-transfer catalyst. It facilitates the transfer of reactants between immiscible phases, enhancing reaction rates and yields. This compound is particularly effective in halogenation reactions, where it helps introduce bromine or iodine atoms into organic molecules. It is also employed in the synthesis of pharmaceuticals and fine chemicals, where precise halogenation is crucial. Additionally, it finds use in polymer chemistry for modifying polymer properties through halogen incorporation. Its role in facilitating efficient and selective reactions makes it valuable in various industrial and research applications.