Recently GBL has become an important solvent for the development of organic perovskites (such as Methylammonium lead halide), novel solar cell materials that can be processed from solution. GBL is a good solvent for the precursor salts such as lead halides and methylammonium iodide or formamidinium iodide. Often mixtures of GBL and DMSO yield best results. GBL is an alternative to the more toxic solvent dimethylformamide that was used in the earlier stages of the development of the perovskite solar cell.