Noteworthy that the glum values of 1-R and 1-S show clear nonlinear dependence on temperature, and they change less drastically below 273K (Figure , Figure ). Such stabilization of luminescence dissymmetry factor values below 273K correlates with the inhibition of rotational motions in phenylene moieties of NHC ligands observed by SS 2 H spin-echo NMR (Figure , bottom). Therefore, we presume that the presence of rotational motion may also affect the dissymmetry factor values of 1-R and 1-S. In this case, the intramolecular rotational motion, especially the 4-fold 90° motion mode of the Ph moiety, can lead to the existence of temporary conformations where all Ph groups have the same orientation relative to their NHC ligands and are equivalent in the structure (Figure ). This, in combination with some librational motion of the PP moiety, may result in the appearance of a symmetry of complex higher than C2, approaching D2 symmetry by the emergence of two additional perpendicular 2-fold axes of rotational symmetry (Figure ). Such symmetry alteration may not strongly affect the general emission properties of the complexes but should more significantly impact the chiroptical properties. This may explain the decrease in glum values with temperature elevation as well as some decrease in the CD signal (Figure ). Conversely, the inhibition of one of the internal motions below 273K should lead to the full domination of the lower symmetry C2 conformation of 1-R and 1-S observed by SCXRD, resulting in a stronger chiroptical response. However, due to the presence of the second 2-fold type of rotational motion which is still quite fast below 273K, no full stabilization of luminescence and CPL intensities were observed in the studied temperature range.