The thermodynamic feasibility of a photo-redox reaction can be evaluated by ionization potential (IP) and electron affinity (EA) values. The IP can be associated with the absolute energy of the valence band edge after alignment with a reference level. The EA is taken to be the difference between the IP and the band gap. This association is an approximation since Kohn-Sham energy levels are affected by the derivative discontinuity where common density functional approximations (Generalized gradient approximation (GGA), Meta-GGA, and Hybrids) differ from experimental values. The reference level can be estimated by determining the vacuum potential in the pores where the variation of the electrostatic potential is the smallest, similar to what has been previously reported for MOFs and COFs. The obtained absolute energies of IP and EA can then be used to select materials whose band edges align with the target redox potentials of the desired reactions, all referenced to vacuum. Hence, in this way, we ensure the thermodynamic feasibility of the desired reaction. In the case of hydrogen (HER) and oxygen (OER) evolution reactions, the redox potentials at pH 0 are -4.4 eV and -5.63 eV aligned to the vacuum level, 17 respectively.