The band edge alignment shown in Figure allows us to easily see if our materials are suitable for photocatalytic reactions of interest, such as oxygen evolution and hydrogen reduction. In this figure, we plot the relative levels for a standard hydrogen electrode (SHE, H + /H 2 ) at -4.44 eV w.r.t. vacuum or 0 eV w.r.t. SHE, and standard oxygen electrode (SOE, O 2 /H 2 O) at -5.67 eV w.r.t. vacuum or 1.23 eV w.r.t. SHE. The CBM for all of our semiconducting materials falls within a range of -1 to -2 eV vs. SHE (refer to energy axis on the right side of the plot), which is more negative than that of H + /H 2 (0 eV), resulting in the ability to reduce hydrogen through photoexcited electrons in these materials. On the other hand, only one of our materials (Ni-01a) has its VBM for both spin channels below the oxygen evolution level (1.23 eV vs. SHE), making this material a potential candidate for oxygen evolution catalysis. Furthermore, we observe that the Ni d-band center for Ni-01a is relatively close to the Fermi level compared to other Ni-intercalations, which is known to be a descriptor of strong binding interactions with reactants and enhanced catalytic activity. As previously mentioned, through intercalation, we achieve a wide range of electronic properties for this family of intercalated bilayer 2D COFs. From the information in Table , we see that twenty-eight out of the sixty-three intercalated 2D COF structures have direct bandgaps in at least one of their spin channels (Cr-02, Cr-03, Cr-04a, Cr-04b, Cr-05, Cu-04a, Fe-01, Fe-04a, Fe-04b, Mn-01a, Mn-03, Mn-04a, Mn-04b, Mn-05, Ni-04a, Sc-02, Sc-03, Sc-04a, Sc-04b, Sc-05, Ti-03, Ti-04a, Ti-04b, V-01a, V-03, V-04a, V-04b, V-05). It is important to note that in all of these cases, the direct bandgaps correspond to the smallest spin-polarized bandgap value. Electronic excitation from valence to conduction band in direct bandgap semiconductors does not require electrons' momentum to change, e.g. via phonon interactions. Therefore, this type of semiconductors are preferred for applications that require efficient photon absorption and photon emission. Our materials have a wide range of direct bandgap values, from 0.20 to 2.02 eV. Three of these materials have the ability to absorb and emit photons in the visible range: Cr-03, Ti-03, and V-03; since their smallest spin-polarized bandgap value falls between 1.65 and 3.26 eV (visible light spectrum). Interestingly, these materials have a similar structure, as they present a TM-03 intercalation pattern (with the intercalants positioned at the centroid of all benzene rings). The spin-polarized band structures and projected DOS for these materials are plotted in Figure . In this figure, we observe the important role of the transition metals, which provide electron density from their 3d-orbitals near the Fermi level. The transition metals and carbon atoms provide the largest electron density at the CBM/VBM. Thus, it is evident that the carbon 2p-orbitals in the COF layers hybridize with the TM d-orbitals, providing the unique direct-semiconducting electronic structures observed. These results confirm our hypothesis that promoting pd orbital interactions between the COFs and TMs leads to a modification of the electronic structure and properties of these systems. Furthermore, Ti-04a, V-04a, and V-01a-which are also direct semiconductors-have their larger spin-polarized bandgaps in the visible range and, although less likely, these visible-range direct transitions can also occur for these materials.