γ-Butyrolactone-d6 is primarily used as a deuterated solvent in nuclear magnetic resonance (NMR) spectroscopy. Its deuterated form allows for clearer and more precise analysis of molecular structures by reducing interference from hydrogen signals. This makes it particularly valuable in research and development for studying organic compounds, polymers, and pharmaceuticals. Additionally, it serves as a labeled internal standard in mass spectrometry, aiding in the accurate quantification of substances in complex mixtures. Its applications are crucial in fields such as chemistry, biochemistry, and material science, where precise molecular analysis is essential.