Used as an analytical reagent for the detection and determination of trace amounts of bromide and iodide ions in solution. It forms insoluble ion-pair complexes with these anions, allowing for gravimetric or spectrophotometric analysis. Also employed in organic synthesis as a precursor for pyridinium-based ionic liquids and as a catalyst modifier in phase-transfer reactions. Its strong quaternary ammonium character enhances solubility and reactivity in biphasic systems.