The remarkable potential for inexpensive upscale of solution processing technologies is expected to enable chalcogenide-based photovoltaic systems to become more widely adopted to meet worldwide energy needs. Here, we report a thin-film solar cell with solution-processed Cu(In,Ga)(S,Se)2 (CIGS) absorber. The power conversion efficiency of 15.2% is the highest published value for a pure solution deposition technique for any photovoltaic absorber material and is on par with the best nonvacuum-processed CIGS devices. We compare the performance of our cell with a world champion vacuum-deposited CIGS cell and perform detailed characterization, such as biased quantum efficiency, temperature-dependent electrical measurement, time-resolved photoluminescence, and capacitance spectroscopy. Copyright © 2012 John Wiley & Sons, Ltd.