Tetrahydrofuran-d8 (THf-d8 TDf) is a deuterated NMR solvent useful in NMR-based research and analyses. 1H NMR line shape analysis of the exchange rates of proton between methanol and acetic acid dissolved in THf-d8 was reported. It participates as a solvent in the synthesis of deuteriotris[bis(trimethylsilyl)amido]thorium and deuteriotris[bis(trimethylsiiyl)amido]uranium. Dynamic NMR spectroscopic study of 15N 15NAE-dipentadeuterophenylformamidine (DPfA) has been studied in THf-d8.