level is closer to the doublet TD energies than the Q '"/$ level in the presence of the positive J and of the external magnetic field, contributing to the strong center emissive line by the powder averaging (eq. 12). When the T+D activation motion is considered, the strong A/E/E/A/A/E polarization pattern is obtained in the quartet fine structure in Fig. . This is rationalized by the preferential populations in Q &"/$ and in Q '"/$ by the selective D ±"/$ -Q ±"/$ interconversions at the T+D activation in the weak exchange coupling. However, the center emissive polarization is weaker. As shown by the red line in Fig. , the strong E/A/E/A and the strong sharp center peak polarization are explained by considering the two different anisotropic motions in the TD system. Also, the E/A/E/A fine-structure region is narrower in Fig. than the corresponding spectrum region in Fig. . This is explained in terms of spectrum narrowing by the gigahertz motional averaging due to the conformation changes in the triplet moiety of the dyad molecule (Fig. ) coupled with the J, D-modulation at room temperature. Therefore, this narrowed E/A/E/A polarization directly demonstrates that the large anisotropic intramolecular conformation dynamics with the gigahertz dihedral angle of b = 45 (and 70) degrees (Fig. ) induce the anisotropic Q-D decoherence to generate the quartet spin polarization.