Sodium tetraphenylborate is widely used in analytical chemistry as a reagent for the determination of potassium, ammonium, and certain organic cations, as well as some transition metal ions. It forms insoluble precipitates with these ions, allowing for their separation and quantification. In organic synthesis, it serves as a phase-transfer catalyst, facilitating reactions between compounds in different phases. Additionally, it is employed in the preparation of organoboron compounds and transition metal complexes, and as a stabilizer in some polymer systems, including coatings. Its applications extend to the pharmaceutical industry for the synthesis and analysis of bioactive compounds. Its ability to form stable complexes with cations also makes it useful in ion-selective electrodes for electrochemical sensing and ion transport studies.