Disclosed are certain polymeric compounds and their use as organic semiconductors in organic and hybrid optical, optoelectronic, and/or electronic devices such as photovoltaic cells, light emitting diodes, light emitting transistors, field effect transistors, and photodetectors. The disclosed compounds can provide improved device performance, for example, as measured by power conversion efficiency, fill factor, open circuit voltage, field-effect mobility, on/off current ratios, and/or air stability when used in photovoltaic cells or transistors. The disclosed compounds can have good solubility in common solvents enabling device fabrication via solution processes.