The phase behaviour and optical properties of a cholesteric ternary copolymer, containing nematogenic phenylbenzoate, cholesteric, and photochromic diarylethene side groups, and its mixture with 2 wt.-% fluorescent dopant were studied. The investigation of the kinetics of a photo-chemical opening-cycle process of the photochromic groups in the cholesteric mixture proved the enegry transfer from the fluroescent dopant to the photochromic diarylethene groups. It was shown that the fluroescence dopant could be controlled by the portion of the "closed" form of the diarylethene groups. During photocyclization of the photochromic groups a "degeneration" of the selective light reflection of the cholesteric matrix observed.