Novel molybdenum dithiolene compounds having neighboring amide groups as models for molybdoenzymes, (NEt4)(2)[(MoO)-O-IV{ 1,2-S-2-3,6-(RCONH)(2)C6H2}(2)] (R = CH3, CF3, t-Bu, Ph3C, were designed and synthesized. The contributions of the (NHS)-S-... hydrogen bond to the electrochemical properties of the metal ion and the reactivity of the O-atomtransfer reaction were investigated by a comparison with [(MoO)-O-IV(1,2-S2C6H4)(2)](2-). The MoOS4 core of [Mo-IV{1,2-S-2-3,6-(CH3CONH)(2)C6H2}2](2-) shows no significant geometrical difference from that of [MoIVO(1,2-S2C6H4)2](2-) in the crystal. The hydrogen bonds positively shifted the Mo-IV/IV redox potential and accelerated the reduction of Me3NO.