[M(ligand)XW11O39] q- XO4, q = 4 XO4, q = 5 XO4, q = 6 Sc a PO4 Cr a PO4 Zn a PO4 [M(ligand)X2W17O61] q- XO4, q = 6 XO4, q = 7 XO4, q = 8 Sc Cr PO4 The large majority of publications that report computed redox potentials ware conducted without accounting for counter-cations and incorporating solvation by means of a polarizable continuum model. For example, Aparicio and co-workers computed reduction potentials corresponding to the tungsten waves in mono-substituted Keggin, [XMW11O40] q-, anions accounting for solvation using the conductor-like screening model (COSMO). Such simplifications can produce large uncertainties in the computed reduction potentials. However, shifts in the reduction potentials were successfully reproduced, relative to the plenary Keggin anion. . Recently, Rosch and co-workers reported the redox behaviour of tri-Mn-substituted Keggin, across several GGA (PBE) and hybrid functionals. The authors included Li + counterions, required for charge neutralization and concluded the structural geometries are not affected by the arrangement of the Li counter-cation in solution. . XC-functionals with increasing contributions of Hartree-Fock exchange (0 % PBE , 10 % TPSSh, 20 % B3LYP, 25 % PBE0) produced larger overestimations of the experimental reduction potentials. The closest agreement with experiment was shown to be the GGA-PBE functional, due to fortuitous error cancellation. Electrochemical behaviors of mono-substituted polyoxotungstates can be fine-tuned by changing the composition and framework. Accurately modelling Keggin, [M(H2O)PW11O39] q-, and Wells-Dawson, [M(H2O)X2W17O61] q-, anions in solution is challenging without experimental comparison as their individual speciation profiles depends on factors (pH, concentration etc.) that are not accounted for in quantum mechanical calculations. In this current work, Density Functional Theory (DFT) computations were employed rationalize the structure-activity relationships of the Keggin, [M(H2O)PW11O39] q-, and Wells-Dawson, [M(H2O)X2W17O61] q-, anions which are integral precursors for several electrochemical reactions. All calculations presented in this work will concern POMs with known experimental syntheses.