A step towards low-cost thin-film electronics is achieved, based on the microwave-assisted synthesis of In2O3:Sn (ITO) nanoparticles in ionic liquids (see figure). Ink-jet printed layers of the ITO nanoparticles on plastics exhibit a high transmittance and conductivity, without the need for performing any conventional thermal post-treatment. Significantly improved layers with higher conductivities are to be expected from high-quality printing.