A new Schiff base 4-[N-hydroxyethyl-N-(methyl)amino]benzaldehyde S-methyl dithiocarbazate (HL, where H is a dissociable proton) and the ruthenium complex [Ru(bpy)2L]PF6 (bpy = 2,2¢-bipyridine) have been synthesized. The structural determinations of the ligand and its ruthenium complex, by X-ray crystallography, show that the ligand is coordinated as a monoanionic bidentate N, S-donor, forming a four-member chelate ring with a bite angle of 65.91
. The complex shows intense MLCT transitions in the visible region. Fluorescent and electrochemical properties have been also studied. The complex in DMF solution exhibited a strong twophoton absorption (t.p.a.) at 532 nm nanosecond laser pulses. The t.p.a. coefficient b, t.p.a. cross-section r and the third-order optical nonlinearity v(3) of the complex and the ligand have been determined by the Z-scan technique.