Butterfly-shaped cluster [MoOS~3Cu~2(PPh~3)~2(Py)~2](1) has been synthesized by low-heating solid state reaction. Another new cluster [MoOS~3Cu~2(PPh~3)~3(Ph)](2) is obtained by the reaction of cluster (1) with PPh~3. Both clusters exhibit good nonlinear optical (NLO) absorptive properties. Their NLO absorptive indices are 1.5×10^- ^1^1mW^-^1 and 3.3×10^-^1^0mW^-^1 respectively.

Key words: NON LINEAR OPTICS, ABSORB COEFFICIENT, MOLYBDENUM COMPOUNDS, SULFUR COMPOUNDS