1,2-Bis(2-methyl-1-benzothiophen-3-yl)perfluorocyclopentene derivatives having diphenylethenyl substituents at 6- and 6'-positions of the benzothiophene rings were synthesized. The mono and disubstituted derivatives formed an amorphous state and the glass transition temperatures were observed at 67 degreesC and 92 degreesC, respectively. Reversible photocyclization reactions were observed in the amorphous state.