The structures of several recently reported organometallic NLO chromophores, (thio-phene) manganese tricarbonyl cations, were fully optimized at the DFT non-local (GGA) level. The calculated results show that the fragments 2-SC4H3CH=CHC6H4-R in these organometallic chromophores are not planar with dihedral angles of 42.2~59.8 between two aromatic rings, which are different from those of uncoordinated counterparts. Based on the DFT geometry opti-mization, the second-order nonlinear optical polarizabilities were calculated by using RPA method. The calculated results indicate that incorporation of +3Mn(CO) unit with thiophene leads to a sub-stantial increase in the second-order polarizability (b). The structures of several recently reported organometallic NLO chromophores, (thio-phene) manganese tricarbonyl cations, were fully optimized at the DFT non-local (GGA) level. The calculated results show that the fragments 2-SC4H3CH = CHC6H4-R in these organometallic Based on the DFT geometry opti-mization, the second-order nonlinear optical polarizabilities were calculated by using the RPA method. The calculated amount of chromophores are not planar with dihedral angles of 42.2-59.8 between two aromatic rings results indicate that incorporation of + 3Mn (CO) unit with thiophene leads to a sub-stantial increase in the second-order polarizability (b).