For the synthesis of our two target polymers, poly(PCT-T) and poly(PCT-2T) (Figure ), we opted for a Stille coupling polymerization reaction, requiring (di)halogenated and (di)stannylated monomers. While the distannylated thiophene and bithiophene comonomers could be sourced from commercial suppliers, dihalogenated PCT was synthesized following our recently reported protocol, which gives dibrominated PCT (diBr-PCT) as a mixture of two regioisomers, namely trans-diBr-PCT and cis-diBr-PCT (Figure , left). As previous attempts to separate the two regioisomers were unsuccessful, diBr-PCT was deployed as an isomeric mixture in our polymerization reactions. The ratio of the two regioisomers was estimated to be 1:1.06 from the 1 H NMR integrals of the peaks assigned to the phenylene-Hs next to the bromine atom as well as the peaks assigned to the phenylene-Hs of the unsubstituted phenylene units (Figure ). Both types of phenylene-Hs gave the same ratio.