The syntheses, X-ray structural characterizations, and electrochemical properties of four new paddlewheel [MMo2(SNO5)4Cl](n−1)+ (Mn+=Na+, Ca2+, Sr2+, Y3+; HSNO5=monothiosuccinimide) compounds are described here. By changing the Mn+ cation charge and size, we demonstrate a method for easily tuning the Lewis acidity of the MoMo quadruple bond and the [Mo2]4+/5+ redox potential. As the charge of the Mn+ cation is increased, the distal Mo atom becomes more Lewis acidic, leading to a shorter Mo2–Cl bond distance, and the [Mo2]4+/5+ redox couple becomes less accessible. As the Mn+⋯Mo2 distance is increased, the distal Mo atom becomes less Lewis acidic, leading to a longer Mo2–Cl bond distance.