This work reports results of a study carried out to optimize the preparation conditions of Cu 2 ZnSnS 4 (CZTS) thin films grown by sequential deposition of Cu 2 SnS 3 (CTS) and ZnS layers, where the Cu 2 SnS 3 compound was grown using a novel procedure consisting of simultaneous precipitation of Cu 2 S and SnS 2 performed by diffusion membrane assisted chemical bath deposition (CBD) technique.The precipitation across the diffusion membranes allows achieving moderate control of release of metal ions into the work solution favoring the heterogeneous growth mainly through an ion-ion mechanism.Through a parameters study, conditions were found to grow Cu 2 SnS 3 thin films which were used as precursors for the formation of Cu 2 ZnSnS 4 films.The formation of CZTS thin films grown in the Cu 2 ZnSnS 4 phase was verified through measurements of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy.Solar cells with efficiencies of 4.9% were obtained using CZTS films prepared by membrane assisted CBD technique as absorber layer.