<p>Zinc-manganese redox flow batteries have attracted extensive interest due to their low cost, high safety, and abundant raw material resources. However, Mn³⁺ is highly prone to disproportionation in aqueous solutions, during which the generated MnO₂ gradually deposits on the electrode surface, consuming active manganese species and blocking interfacial reactions. This process leads to capacity fading and poor cycling stability, severely limiting the further development of this system. Because the disproportionation of Mn³⁺ cannot be fundamentally eliminated through conventional approaches, regulating its chemical environment at the molecular level of the electrolyte is essential for effectively suppressing disproportionation and improving reversibility. Among various electrolyte-regulation strategies, constructing a stable Mn³⁺ coordination environment via organic ligands is regarded as an effective route to mitigating disproportionation at its origin. Although previous studies have attempted to stabilize Mn³⁺ by introducing ligands, the suppression of disproportionation has remained modest, and the overall stability and reversibility still fall short of long-term cycling requirements. In this work, sulfosalicylic acid is employed as a multidentate ligand to stabilize Mn³⁺. The functional groups-SO₃H, -COOH, and -OH enable the formation of stable Mn³⁺-ligand coordination structures, thereby minimizing disproportionation and significantly suppressing heterogeneous nucleation and deposition of MnO₂. After 2000 cycles, the capacity retention remains at approximately 80%, and the coulombic efficiency is maintained above 90%, demonstrating that the system exhibits excellent reversibility and stability even under long-term cycling conditions. Therefore, the coordination environment established by introducing sulfosalicylic acid within an appropriate concentration range can effectively stabilize Mn³⁺ and mitigate its disproportionation behavior, thereby providing valuable guidance for the molecular design of electrolytes in aqueous metal-based redox flow batteries.</p>