In this letter, the performance characteristics of single-gate and dual-gate thin-film transistors (TFTs) with amorphous indenofluorene–phenanthrene copolymer semiconductor active layers are reported. Optimized single-gate devices possess mobilities up to 0.15 cm2/V-s and width-normalized contact resistance of 1275 Ωcm. These results were obtained through the combination of a recessed source/drain structure and suitable surface treatments of source/drain contact electrodes. The characteristics of dual-gate indenofluorene–phenanthrene copolymer TFTs with polymer gate insulators are also reported. This structure exhibits increased on-current, reduced threshold voltage, improved sub-threshold swing and increased on–off current ratio compared to single-gate architectures.Graphical abstractHighlights► We report on the electrical characteristics of amorphous copolymer transistors. ► Mobility in excess of 0.1 cm2/V-s was obtained in amorphous organic semiconductor. ► Careful attention was paid to surface treatment of insulator and metal electrodes. ► Dual-gate architectures results in improved sub- and above-threshold characteristics.