Potassium tetraphenylborate is widely used as a precipitating agent in analytical chemistry. It is particularly effective for the quantitative determination of potassium ions in various samples, forming an insoluble complex that can be easily filtered and measured. This property makes it valuable in water quality testing, soil analysis, and pharmaceutical quality control.

In organic synthesis, it serves as a phase-transfer catalyst, facilitating reactions between compounds in different phases, such as aqueous and organic layers. This enhances reaction efficiency and selectivity in the production of fine chemicals and intermediates.

Additionally, it is utilized in the preparation of ion-selective electrodes, where it acts as an ionophore to improve the sensitivity and specificity of potassium ion detection in complex matrices. Its stability and low solubility in water make it a reliable choice for such applications.

In the field of materials science, potassium tetraphenylborate is employed in the synthesis of certain polymers and coordination compounds, contributing to the development of advanced materials with tailored properties. Its unique chemical behavior allows for precise control over molecular structures and functionalities.