Disclosed embodiments provide a solution-based process for producing useful materials, such as semiconductor materials. One disclosed embodiment comprises providing at least a first reactant and a second reactant in solution and applying the solution to a substrate. The as-deposited material is thermally annealed to form desired compounds. Thermal annealing may be conducted under vacuum; under an inert atmosphere; or under a reducing environment. The method may involve using metal and chalcogen precursor compounds. One example of a metal precursor compound is a metal halide. Examples of suitable chalcogen precursor compounds include a chalcogen powder, a chalcogen halide, a chalcogen oxide, a chalcogen urea, a chalcogen or dichalcogen comprising organic ligands, or combinations thereof. Certain disclosed embodiments concern a method for making a solar cell from I-III-VI semiconductors.