Organic redox flow batteries provide a compelling avenue to advance large-scale energy storage due to the synthetic tunability and sustainability of organic active materials. Particularly, aqueous organic redox flow batteries possess attractive technical merits including high current and power performance, low costs, low toxicity, and safe operation. Through rational molecular engineering, a family of two-electron storage viologen anolyte materials were synthesized with the goal of boosting the cell voltage and capacity of organic aqueous redox flow batteries. These viologen anolytes have a theoretical capacity up to 96.5 Ah/L in H₂O, and reduction potentials as low as -0.78 V vs. NHE. In flow battery testing, these compounds showed outstanding two-electron cycling performance when paired with (ferrocenylmethyl)trimethylammonium chloride as a cathode: cell voltage up to 1.38 V, peak power density up to 130 mW/cm², capacity retention up to 99.99% per cycle, and energy efficiency up to 65% at 60 mA/cm². Pairing a two-electron viologen anolyte with a TEMPO catholyte in an aqueous flow battery as a proof-of-concept delivered two-electron cycling with a cell voltage up to 1.72 V. This represents the highest cell voltage reported for an organic aqueous redox flow battery.