Up to date, a huge variety of 2D COF structures has been synthesized and studied, e.g., in the direction of photoactivity and photosensitivity. However, electronic structures are seldom discussed and, even then, mostly only single layers are considered. Thomas et al. investigated electronic structures of 2D -conjugated polymers with three-and fourarm connections, which correspond to kagome and Lieb (Archimedean) lattices, and explained occurrence of flat and disperse bands. However, no stacking was taken into account. On the other hand, Er et al. reported an excellent carrier mobility and photoconductivity along the vertical direction of a DA-COF (D -donor, A -acceptor). The authors found that these properties depend on the number of layers and the stacking of layers. The conduction was achieved by electron hopping between layers, in which the donor and the acceptor groups were aligned with respect to each other. This arrangement would correspond to the AAAA stacking discussed above. In other works on COF systems available in the literature, some of the COFs were reported to have high charge carrier mobilities, as in the case of COF-366 and COF-66, with covalently linked porphyrin units offering extended planar -electron system.