This work is devoted to the study of the orientational mobility of molecular groups of an ionic liquid (IL) in the BMPyrrTFSI system with lithium bistrifluoromethanesulfonylimide (LiTFSI) salt at different lithium concentrations (0 mol, 0.1 mol and 1.5 mol) [1][2]. These systems were studied using NMR relaxometry on a Bruker Avance III 500 MHz NMR spectrometer. Measurements of spin-lattice relaxation rates were carried out at various temperatures in the range from 243 to 333 K for several nuclei: 1H, 13C, 7Li, 19F. The obtained results were compared with the data presented in the literature. At a concentration of 1.5 mol (the most saturated salt solution in IL), we observed a characteristic kink in the graphs during the transition to low temperatures (about 278 K). This change in the character of the dependence possibly indicates both freezing of this system and a rearrangement of the molecular structure. At low concentrations (0.1 mol), as well as for the pure ionic liquid, this effect was not observed in the temperature range studied.