1,2-bis (2-methyl-1-benzothiophen-3-yl) perfluorocyclopentene derivatives having styryl substituents at 6 and 6' positions of the benzothiophene rings were synthesized. The mono-substituted derivative was crystal, while the iii-substituted one formed amorphous state below the glass transition temperature(Tg) of 60 degrees C. Reversibe photocyclization reactions were observed in the amorphous state.