Thin-film technologies represent one step forward in the range of applicability of photovoltaics (PV) since they can be manufactured onto virtually any surface or material giving them an enormous versatility compared to Si-based solar cells. Flexible and light-weight substrates like thin metallic or polymeric foils are particularly attractive for thin-film PV since they allow powering portable electronics, wearables and IoT devices adapting to any shape and without adding extra weight. These characteristics also make them interesting for applications in the space and transportation industry. In addition, flexible substrates are expected to reduce PV fabrication costs through roll-to-roll high-throughput industrial processes. Another interesting niche of application that can benefit from the versatility of thin-film PV is building-integrated photovoltaics (BIPV). Solar devices can be directly deposited on materials commonly used in construction such as ceramics or glazing so that solar devices are made integral parts of buildings reducing manufacturing and installation costs as well as avoiding the need of extra land allocation for power generation which are often regarded as two critical factors that may restrict the massive deployment of photovoltaics. Among thin-film technologies, Cu₂ZnSn(S_1-xSe_x)₄ compounds, also known as Kesterites, stand out by the earth-abundancy and non-toxicity of its constituent elements that makes them compatible with a future mass deployment of PV. Thus, this work explores the implementation of a Cu₂ZnSnSe₄ (CZTSe) sequential fabrication process based on the selenization of sputtered metallic stack precursors onto different substrates: polyimide (PI), stainless steel (SS) and ceramic tiles. However, the increased applicability range of these substrates has a dark side since they lack several favorable properties of soda-lime glass (SLG): favourable thermomechanical properties and beneficial alkali (Na and K) composition that diffuse into the absorber during its synthesis and are fundamental for high efficiency kesterite devices. This way, SS and ceramic possess rough surfaces that complicate the deposition of thin films and detrimental impurities in their composition that can hinder the performance of the devices. As for PI it has a low thermal robustness that limits the synthesis temperature below 500ºC. In addition, none of them contain alkalis thus requiring the development of extrinsic doping procedures. In this work, we present different strategies to overcome the specific problems of each of the substrates and demonstrate their suitability as substrates for CZTSe solar cells.