Cover description: In silico discovery of polymer photovoltaics. Rapid computational screening of conjugated polymers for organic solar cells. Using the common acceptor material, phenyl-C61-butyric acid methyl ester (PCBM), and a simple model of photovoltaic cell efficiency derived from electronic structure properties, over 90000 copolymers were generated “in silico.” A genetic algorithm was used to solve the “inverse design” of copolymers with optimal power efficiency, many with predicted efficiencies over 10%. The method rapidly finds near-optimal structures, suggesting new synthetic directions for polymer photovoltaics. Further screening methods are suggested to refine initial targets into more viable lead compounds.