CuIn(Se x , S 1 − x ) 2 films were prepared by means of non-vacuum, instantaneous, direct synthesis from elemental In, Cu, Se and S particle precursor films by passing an electrical current with precise control through the metal substrate. For a constant reaction period of 1s, unreacted elemental particles remained in the films for powers below 1kVA, whereas the reaction to CuIn(Se x , S 1 − x ) 2 (x=1) appeared to be complete at higher power. Chalcopyrite structure was observed in the range from 1.08kVA to 1.24kVA, the sphalerite structure appeared over 1.35kVA. X-ray diffraction shows single (112) peaks of CuIn(Se x , S 1 − x ) 2 and the peak position agreed with the nominal composition of the precursors.