The replacement of vacuum steps by atmospheric processes can significantly reduce the manufacturing cost of solar cells and modules. Solution‑based processes for PV active layer preparation is an attractive alternative which does not require vacuum systems. In particular, solution-based Cu₂ZnSn(S,Se)₄ (CTSSe) precursors have drawn the attention of the PV community because of the promising results that have been already obtained (record efficiency of 12.6%).  Although the use of spin coating has led to the best reported efficiencies, the potential transfer of this technique to the industry is unclear. In this sense, inkjet printing in comparison to spin coating exhibits a better utilization of material, the potential of processing large areas, the compatibility with roll-to-roll technique and, finally, the capability to write specific patterns without the use of masks.In this work, a CZTS ink was prepared using metallic salts and DMSO as precursor and solvent, respectively. Inkjet printing was used to deposit the ink onto molybdenum‑covered glass substrates. Three layers of the CZTS ink were sequentially printed with a drying step in between (at 200°C for 10 min under non-controlled atmosphere).  Two different selenization strategies of the CZTS precursor were studied:  (1) one-step thermal treatment at 540°C for 20 min under 1 bar Ar‑Se reactive atmosphere and (2) two-step treatment at 400°C for 30 min under 1 mbar Ar‑flow and 550°C for 15 min under 1 bar Ar‑Se reactive atmosphere. In addition, the doping of the absorber with Ge and Na atoms was also investigated. Finally, solar cells of 0.09 cm2 were fabricated and the effect of post-annealing (180°C for 20min) and light soaking treatments on the cell performance was studied. Regarding the main results obtained, it can be highlighted that the one-step selenization led to better solar cells before the post-annealing and light soaking treatments. Nevertheless, after the post-annealing, both selenization strategies led to similar efficiencies. Regardless the selected selenization strategy, an enhancement of short circuit current and solar cell conversion efficiency was observed after post-annealing. The open circuit voltage and the fill‑factor of the devices remained almost unaltered throughout the post‑annealing treatments.  Furthermore, the addition of Ge improved the open circuit voltage by doubling its value in comparison with the reference non-doped cells. The addition of Na increased the efficiency mostly because of the reduced series resistance of the cells. Finally, an excessive addition of Na was detrimental to solar cell performance.