Chlorotriethylphosphine gold(I) is primarily used in the field of catalysis, particularly in organic synthesis. It serves as a catalyst in various chemical reactions, including the formation of carbon-carbon and carbon-heteroatom bonds. This compound is especially valuable in the synthesis of complex organic molecules, where it facilitates efficient and selective transformations. Additionally, it is employed in the preparation of gold nanoparticles, which have applications in electronics, medical imaging, and targeted drug delivery. Its stability and reactivity make it a crucial component in advanced material science and nanotechnology research.