The enzyme-catalyzed synthesis of poly(p-ethylphenol) (PEP) was modified by copolymerization with polycarbonates through triphosgene at low temperature to form polycarbonate-co-poly(p-ethylphenol) (PC-co-PEP). FTIR, NMR, GPC, and thermal analysis verified the formation of PC-co-PEP. The copolymers have an optical absorption in the UV range. CdS semiconductor nanocrystallites were synthesized in reversed micelles with subsequent in situ enzymatic copolymerization of p-ethylphenol and 4-hydroxythiophenol in the same medium. TEM and ATR-FTIR showed that the polymer precipitated in spherical morphologies, incorporating CdS nanocrystals into the polymer matrix, with surface hydroxyl groups. The polymer/CdS core was then dispersed into polycarbonate. The polymer/CdS nanocomposites showed higher optical aborbance in the UV-vis range when compared to the polymer matrix without CdS.