In the second stage, new donor polymers are designed. A monomer library composed of 1,210 units was created from compounds with three or fewer fused rings from OPEP2 and other small conjugated organic molecules. Oligomers with six monomer units were designed, with a maximum of two unique monomers and any sequence arrangement being permissible(e.g. ABBABA, ABABAB, etc.). For evaluation of fitness within the GA, each donor was screened against the top 200 NFAs from GA runs 1-3. To ensure that the proposed oligomers would act as donors, a check was set within the GA to guarantee that the energy levels were aligned with at least 25% of the acceptors.