The solid-state optical reflectivity studies of the partially desolvated form 1•2DMF was performed in the temperature range of 10-300 K (Figure , left) and also under light irradiation at 10 K (Figure , left). At 300 K, a broad absorption band centered at around 550 nm was observed which is associated with the MLCT transition coming from HS Fe(II) center (Figure , left). Upon decreasing the temperature, the spectra were clearly modified, and a decrease of the absorption band at 550 nm was observed whereas a strong absorption band centered at 700 nm was observed at 10 K, which is due to the change in the spin-state of Fe(II) HS to the Fe(II) LS state (Figure , left).