The optimized structures of CP1-T and CP2-T reveal high planarity of the extended conjugated backbone (main chain. Figures ), where majorly contribute to the HOMOs. Analogous to small molecules 1 and 2, the LUMOs of the two polymers are also mostly located on the carbonylpyridinium units. Both polymers exhibit a dozen of low-lying orbitals from LUMO to LUMO+11 that could potentially be involved in relevant reductive processes (the lower/upper values are -3.8/-2.1 eV for CP1-T, -3.9/-2.7 for CP2-T, Figure ). Moreover, the introduction of an electron-withdrawing benzothiadiazole unit significantly lowers the LUMO in CP1-T.