Benzyltriethylammonium borohydride is primarily used as a reducing agent in organic synthesis. It is particularly effective in the reduction of carbonyl compounds, such as aldehydes and ketones, to their corresponding alcohols. The chemical is favored in reactions where a mild and selective reducing agent is required, as it operates under relatively mild conditions and offers good control over the reduction process.

In addition to its role in reducing carbonyl compounds, it is also utilized in the reduction of imines to amines, which is a crucial step in the synthesis of various pharmaceuticals and agrochemicals. Its ability to function in both aqueous and organic solvents makes it versatile for a range of applications.

Furthermore, benzyltriethylammonium borohydride is employed in the preparation of metal nanoparticles, where it acts as a reducing agent to convert metal salts into their respective nanoparticles. This application is significant in the field of nanotechnology, where nanoparticles are used in catalysis, electronics, and medical diagnostics.

Overall, its utility as a reducing agent in diverse chemical transformations underscores its importance in both academic research and industrial processes.