The homometal cluster [Fe(DMF) 6 ][Mo 2 (μ 2 -S) 2 S 4 ] 1 (DMF=dimethylformamide) was successfully synthesized by low-temperature solid-state reactions. X-ray single-crystal diffraction studies suggest that compound 1 is dinuclear anion cluster. The compound was characterized by elemental analyses, IR spectra and UV–vis spectra. The third-order non-linear optical (NLO) properties of the cluster were also investigated and exhibited nice non-linear absorption and self-defocusing performance with modulus of the hyperpolarizabilities 4.20×10 −30 esu for 1.