A series of fluorinated ester-functionalized conjugated polythiophenes and their random copolymers with 3-octylthiophene (OT) were synthesized by oxidative polymerization with FeCl3 in supercritical carbon dioxide (scCO(2)). The polymerizations were compared with those prepared from the conventional solvent, chloroform, in terms of yield, molecular weight, and polydispersibility. The effects of side-chain organization of polythiophenes with different types of fluoroalkyl esters on their solubility in scCO(2) were also investigated. While homo-polymers of poly[(2-(3- thienyl) acetyl 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanate)] (PSFTE) and poly[ 2-( 3- thienyl) methylheptafluorobutyrate] (PFTE3) show solubility in scCO(2), polymers prepared from fluorinated esters of 3-thienylmethanol were found to be insoluble in both scCO(2) and common organic solvents. The copolymers, P(OT-SFTE), with different molar compositions of comonomers prepared in CO2 were also soluble in scCO(2).