Used primarily as a labeled compound in research and analytical chemistry, it serves as a deuterated analog of 3-ethylaniline. Its deuterium labeling makes it valuable in mass spectrometry and NMR studies, aiding in the identification and quantification of compounds in complex mixtures. It is also employed in metabolic studies to track the pathways and transformations of chemicals in biological systems. Additionally, it can be utilized in the synthesis of deuterated pharmaceuticals or intermediates, ensuring accurate analysis of drug metabolism and pharmacokinetics.