Donor substituted heteroleptic bis-tridentate Ru(II) complexes with different deprotonated forms exhibit larger alterations of the first hyperpolarizabilities in oxidized process and are promising to become redox-switchable nonlinear optical (NLO) molecular materials. For systems with diprotonated form, the β vec value of the two-electron-oxidized system 1 3 2+ is 5.3 and 178.6 times as large as those of the reduced parent 3 and the one-electron-oxidized system 3 + according to the DFT–FF results. For systems with mono-protonated form, the oxidization of the deprotonated benzimidazole anion is more helpful to enhance the β vec value because of the increasing β x component. For systems with fully deprotonated form, the largest ratio of |β vec ((1″) + )/β vec (1″)| of the system without substituent is about 13.2 due to the dominant off-diagonal tensor β zxx . And the time-dependent density functional theory (TDDFT) results indicate that the charge transfer transition of the first excited state displays an indispensable role for larger off-diagonal tensor. Finally, the calculated frequency-dependent β results exhibit a small dispersion effect at the low-frequency region.