Ru(salalen)(CO)(2) complexes were found to serve as catalysts for asymmetric sulfimidation under irradiation, and high enantioselectivity (up to 90% ee) was obtained. In addition, the structures of two Ru(salalen)(CO)(2) complexes that carry the ligands of the same configuration but induce opposite asymmetry to each other, were determined by X-ray diffraction analysis.