Choline iodide is primarily used in organic synthesis as a reagent for the preparation of other choline salts and compounds. It is particularly valuable in the synthesis of quaternary ammonium compounds, which have applications in various industrial processes. Additionally, it serves as a precursor in the production of pharmaceuticals, where it is utilized to develop drugs that target neurological and liver-related conditions. In the field of materials science, choline iodide is employed in the creation of ionic liquids, which are used as solvents in chemical reactions and as electrolytes in advanced battery technologies. Its role in these applications highlights its versatility and importance in both chemical and industrial research.