The photochromic diarylethene, 1,2-bis(1,4-dimethyl-2-phenyl)perfluorocyclopentene has been synthesized and its single crystal can be obtained in hexane at -4℃. The structure of diphenylperluorocyclopentene bearing C2/c space group and monoclinic crystal system is very different from that of dithienylperfluorocyclopentene derivatives bearing Pī space group and triclinic crystal system by X-ray crystallographic analysis. The compound undergoes the phototchromic reaction in solution but no optical activity in single crystal. In addition, its optimum conformation in solvent is also discussed. The photochromic diarylethene, 1,2-bis (1,4-dimethyl-2-phenyl) perfluorocyclopentene has been synthesized and its single crystal can be obtained in hexane at -4 ° C. The structure of diphenylperluorocyclopentene bearing C2 / c space group and monoclinic crystal system is very different from that of dithienylperfluorocyclopentene derivatives bearing Pī space group and triclinic crystal system by X-ray crystallographic analysis. The compound undergoes the phototchromic reaction in solution but no optical activity in single crystal. In addition, its optimum conformation in solvent is also discussed.