We demonstrate an additive ink-jet process to fabricate homogeneous CdS semiconductor films for thin film transistors (TFTs). This process combines in-situ synthesis with ink-jet printing at a maximum processing temperature of 250 C. The solvent in the reaction is used to dissolve the cadmium and sulfur precursors. The reaction to form the CdS films takes place in a solid-state mode. This method does not require preliminary nanoparticles synthesis or organic stabilizers and results in film with near zero precursor waste. TFTs with mobilities of 7.5× 10− 2 cm 2/V· s, threshold voltage (V T) of 3.4 V and on/off current ratio of 8× 10 4 were demonstrated.