Molecular rotors, or amphidynamic crystals, which consist of static groups and dynamic components, have a rich potential to provide functional properties such as ferroelectricity and to control them by molecular motion. A nuclear magnetic resonance (NMR) relaxation study, which is very important to elucidate molecular motion in amphidynamic crystals, is described. In the molecular complexes having 1,4-diazabicyclo[2.2.2]octane (DABCO) as a rotator, DABCO reorientation about its pseudo C3 rotation axis was shown to reach up to the order of 10−1 THz around the phase transition temperature, which frequency is comparable to that of motion in the liquid phase. The correlation time of reorientation is compared with the free rotation time of a hypothetical free rotator.