This implies that the nitrogen vacancies can trap electrons, localized state within the band gap of the monolayer, as shown in Figure . For the monolayer, a band gap value of 3.4 eV was calculated, significantly larger than the experimental values of 2.7 eV due to the reduction in dimensionality. To estimate the accuracy of given defects, we calculate the DFEs and TILs of all nitrogen vacancies in a g-C3N4 bulk supercell at same level of theory. The obtained bulk band gap value of 2.9 eV closely aligns with the experimental values, shown in Table . Defect TILs remain deep in the band gap, while being shifted downwards in energy.