Tetrabutylammonium tetraphenylborate is widely used as a phase-transfer catalyst in organic synthesis, facilitating the transfer of reactants between immiscible phases, such as aqueous and organic layers. It is particularly effective in reactions like nucleophilic substitutions and esterifications, where it enhances reaction rates and yields. In analytical chemistry, it serves as an ion-pairing agent, aiding in the separation and detection of ions in techniques like high-performance liquid chromatography (HPLC). Additionally, it is employed in electrochemical studies as a supporting electrolyte due to its stability and conductivity in non-aqueous solutions. Its role in synthesizing and characterizing ionic liquids and other specialized materials is also noteworthy.