Compared to the single-band characteristics of the 2D unary HT-polymers, both the valence and conduction bands of 2D CTPAB, OTPAB and MTPAB near the Fermi level show pronouncedly dispersed bands due to the reduced symmetry from the unary counterparts. Since the HT-polymers are of honeycomb-kagome topology, the band structure around the Fermi level is dictated by the center atoms at the crystallographic positions (1/3, 1/3) and (2/3, 2/3). Therefore, the band structure can be coarse-grained by a tight-binding model (Equation ) for the honeycomb network with two atoms per unit cell. In case both atoms have the same on-site energy, the band gap is similar to the well-known band structure of graphene, as shown in Figure . However, if the on-site energies are not equal, which models the situation in h-BN, a band gap opens (Figure ). In this case, the band gap is of the size of the difference in on-site energy. It can be found that the band structures of the binary HT-polymers (Figure ) are similar to that of h-BN even though the boron and nitrogen centers are 1 nm apart from each other. This result is fully in line with our previous study, demonstrating the importance of lattice topology in controlling the electronic structures of HT-polymers. Details on the calculated carrier mobilities are given in Figure and Table .