1-Bromobutane-d9 is used as a deuterated starting material in chemical synthesis, particularly in reactions requiring the tracking of atom or molecule movement. The deuterium (D) atoms in its structure enable easy monitoring through techniques such as NMR spectroscopy. It is also applied in studying reaction mechanisms and molecular-level chemical processes, as well as in pharmacological research for developing new drugs, utilizing deuterium's unique properties to enhance chemical stability and efficacy.