A new photoluminescent (PL) polymer, alkylfluorene-benzothiadiazole-benzylidenylfluorene copolymer, was synthesized by a Suzuki coupling reaction, and its optical properties and applicability as a color conversion material were studied. The synthesized PL polymer showed good thermal stability and superior color conversion ability which converts blue light into green. A color conversion film was fabricated using a screen printing method and its optical properties were analyzed after placing the fabricated color-conversion film on a blue light emission device. The measured brightness was 1120 cd/m(2), which was approximately 346% higher than that measured for the device without a color-conversion film (251 cd/m(2)).