However, the intensity of fluorescence emission in the HS state of the metal center was vast stronger than the LS state, revealed that the effect of change in the spin-state of Fe(II) center was higher than the thermal quenching effect originated through the SCO process. By studying the variable temperature SCXRD structures of (31)vacuum at 100 K and 173 K, it was established that the intermolecular interactions between L23 and SeCN -were prominently decreased with increment of temperature, thus decreasing the efficiency of intermolecular energy transfer and canceling the nonradiative decay, which caused a proper rise in fluorescence intensity at HS states.