The nickel( 11) complex with the new ligand of S-benzyl-beta-N-[10-ethyl-phenothiazine-3-methylene]dithiocarbazate(HL) crystallizes in the triclinic system, space group P (1) over bar with a = 7.516(1), b = 11.322(l), c = 13.366(l) Angstrom, alpha = 84.818(l), beta = 81.688(l), gamma = 76.037(1)degrees, V = 1090.26(3) Angstrom(3), Z = 1, D-c = 1.413 g/cm(3), F(000) = 482, mu(MoKalpha) = 0.774 mm(-1) (lambda = 0.7103 Angstrom), R = 0.0573 and wR = 0, 1375 for 3357 observed reflections with I greater than or equal to 2sigma(I). The HL has lost a proton from its tautomeric thiol form and acts as a single negatively charged bidentate ligand coordinating to the nickel ion via the mercapto sulfur and P-nitrogen atoms. The geometry around Ni( 11) is almost square-planar with two equivalent Ni-N and Ni-S bonds. The nonlinear absorption of HL and NiL2 solutions (in DMF) was measured by open-aperture Z-scan technique at the wavelength of 532 nm.