Octupolar metal complexes for third order nonlinear optical studies

► NLO properties of the complexes have been investigated by Z-scan measurements. ► The complexes exhibit negative nonlinear refractive index. ► The real and imaginary parts of nonlinear optical susceptibility were measured. ► TPA was found to be the major contributor to the observed nonlinear absorption. ► Complexes possess large molecular TPA cross section.