A new green photochromic diarylethene compound, 1,2-bis[2-n-hexyl-5- (2,2-dicyanovinyl)-3-thienyl]-perfluorocyclopentene (1o), was synthesized and its photochemical properties were investigated in detail. The measurement results demonstrated that the compound has good photochromism in solution and in PMMA amorphous film. Upon irradiation with 365 nm light, the colorless of the hexane solution and the PMMA film turned colored and under the visible light irradiation (λ > 510 nm) the colored hexane solution and the colored PMMA film return to colorless.