Sodium tetraphenylboron is widely used in analytical chemistry as a reagent for the determination of potassium, ammonium, and other cations. It forms insoluble precipitates with these ions, allowing for their separation and quantification in various samples. 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 as a stabilizing agent in certain chemical processes. Its ability to form stable complexes with specific ions also makes it useful in ion-selective electrodes for electrochemical measurements.