Used as a phase-transfer catalyst in organic synthesis, particularly in alkylation reactions within two-phase systems, to facilitate efficient reactions between water-soluble and water-insoluble reagents. Commonly employed in the preparation of ethers and esters from phenols and alcohols, as well as other fine chemicals.

Also serves as a strong base for deprotonation of weakly acidic compounds, such as carboxylic acids and phenols, with minimal side reactions due to the large size of the tetrabutylammonium cation, which reduces direct interactions with other species.

In the synthesis of pharmaceuticals and agrochemicals. Widely used in analytical chemistry for titrations, including the determination of free fatty acids in oils and fats, and as a reagent in ion-pairing applications and sample preparation for techniques like HPLC and GC, aiding in extraction and separation.

Additionally, applied in the electronics industry for controlled etching of materials such as silicon dioxide, in semiconductor processing and circuit board manufacturing.

Its solution form, typically ~40% in methanol, provides convenience for precise dosing in liquid-phase reactions.