A series of non-Grignard Mg-electrolytes with various para-substituents was synthesized starting from commercially-available phenols. More electron-withdrawing substituents shift the anodic stability of the electrolyte by 400 mV. The p-CF₃ substituted phenol exhibits the highest stability of 2.9 V vs. Mg^2+/0, and cycles reversibly with the Chevrel-phase Mo₆S₈ Mg-ion cathode.