Tetramethylammonium 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. This reagent is often chosen for its mild and selective reducing properties, which make it suitable for sensitive substrates that might decompose under harsher conditions. Additionally, it is employed in the preparation of metal nanoparticles, where it acts as a reducing agent to convert metal salts into their respective metallic forms. Its application extends to the field of materials science, where it is used in the synthesis of advanced materials and coatings. The compound is also utilized in certain electrochemical processes due to its stability and efficiency in reducing various chemical species.