Used in pharmaceutical research as a deuterated analog to study metabolic pathways and drug interactions, providing insights into the behavior of non-deuterated compounds. It serves as a valuable tool in the development of new therapeutic agents, particularly in the field of oncology, where phthalazine derivatives are explored for their potential anti-cancer properties. Additionally, it is employed in analytical chemistry as a reference standard in mass spectrometry and NMR studies to enhance precision in detecting and quantifying compounds.