We have studied the third-order nonlinearities of Ni(II) and Cu(II) metal-organic complexes in solution using wavelength tunable DFWM experiments in the 550 - 600 nm spectral region associated with d-d transitions introduced by the metal atoms. A room temperature, frequency doubled LiF:F 2- color center laser was used as the tunable laser source for these experiments. Additional resonant enhancement over thermally induced nonlinearities is observed for the Cu-based metal-organic complexes in these DFWM studies. Information about the sign of the nonlinearity and relative roles of nonlinear refraction and absorption was obtained with Z-scan experiments. Energy transmission measurements indicated that nonlinear absorption occurs in all samples. Relationships between the nonlinear response and the spectral absorption features of these metallorganics are discussed.