The acidity of the tetrazole pendants results in nearly complete ionization and a highly polar structure that promotes further electrolyte uptake. The conductivity behavior can be adjusted by tuning the tetrazole content of the polymer and the KOH concentration of the surrounding KOH solution. The technical feasibility of the concept is demonstrated in alkaline water electrolysis tests in 15 wt% at 60 °C, showing performance similar to that of Zirfon and stable performance for nearly 600 h. The present work is merely an example of how the specific functionality, the tetrazole, can be used as a tool for tuning hydrophilicity of high pH tolerant polymers, which are originally too hydrophobic to be used as ion-solvating membranes in concentrated aqueous KOH. Tetrazole possesses high alkaline stability and can easily be attached to affordable and stable polymer chemistries for high performing and stable alkaline ion solvating membranes.