Tetra-n-butylammonium phenyltrifluoroborate is a versatile organoboron reagent widely used in organic synthesis, particularly as a stable, air- and moisture-tolerant equivalent to phenylboronic acid in Suzuki-Miyaura cross-coupling reactions. It facilitates the formation of carbon-carbon bonds between aryl or vinyl halides and the phenyl group, enabling the synthesis of biaryl compounds essential for pharmaceuticals, agrochemicals, and materials. The quaternary ammonium cation provides excellent solubility in both aqueous and organic phases, allowing its use under phase-transfer catalysis conditions to enhance reaction efficiency in biphasic systems. Additionally, it supports nucleophilic substitution reactions by activating anions in non-polar solvents and serves as an intermediate in the preparation of other boronic derivatives.