A diarylethene(1) having cholesterol units was synthesized in an attempt to use it as a dopant to control the phase of liquid crystals. By the addition of the diarylethene, 4-cyano-4'-pentylbiphenyl (K-15)(Tokyo kasei) nematic liquid crystal showed cholesteric liquid crystalline texture. Upon irradiation with UV light, the cholesteric phase was decomposed. The cholesteric phase was recovered by visible light irradiation. The reversible photoinduced-phase change was observed by alternate irradiation with UV and visible light.