A new ligand, S-benzyl-[-N-[10-ethylphenothiazinyl-3yl]-methylene] dithiocarbazate ( abbreviated as HL), and its complexes ML2 (M = Co and Hg) have been synthesized and fully characterized by elemental analyses, EI-MS, H-1 NMR, IR, UV-Vis spectra, and photoluminescence measurement. All ofthe compounds en-tit an olivine color in DMF solution. The emission maximum (lambda(max)(em)), and fluorescence quanturn (Phi(f)) of each compound were measured. Nonlinear Optical propertiesof the HL and ML2 were studied by z-scan technique. Nonlinear absorption coefficient beta were measured to be 0.71, 0.19 and 0.395 cm(.)GW(-1). Theoretical calculations (RHF/PM3) were consistent with the experimental results.