Several groups have introduced layer-by-layer methods to deposit MOF thin films on substrate, first, in 2007, Wöll and Fischer reported on the layer-by-layer route to MOF synthesis, and later H. Kitagawa and coworkers. Such surface-mounted MOFs are referred to as SURMOFs. They exhibit high crystallinity and can be investigated using virtually all surface science techniques, see also Section on SURMOFs synthesis in the Experimental Section. SURMOF-2, being an isoreticular series based on MOF-2, is one of the simplest MOF architectures suited for layer-by-layer growth. They are derived from MOF-2, a bulk framework material based on paddle-wheel units with four dicarboxylate groups and typically Cu 2+ or Zn 2+ -dimers connected to ditopic organic linkers of different length, the shortest one being 1,4-benzene dicarboxylate. The length of the linkers determines the lattice constant and, thus, the pore size of the resulting SURMOFs, where up to 4 nm in diagonal have been reached up thus far. Layers of such SURMOFs form square lattices and, theoretically, could be stacked together in three different arrangements. The most symmetric P4 variant is the eclipsed stacking with linkers and connectors in one layer directly on top of linkers and connectors in another layer (see Figure ). This stacking is found in all SURMOF-2 derivatives discussed in this chapter and leads to a less stable system due to unfavorable Coulomb and van-der-Waals interactions. Computational investigations showed that two other stackings are energetically more favorable. These are slipped and inclined stackings (see Figure and), with P2 or C2 symmetries, respectively, which emerge in bulk synthesis. However, in the SURMOF approach, the metastable P4 symmetry with eclipsed stacking is enforced by the anchoring of the first MOF layers to the nucleating surface. [112] at the DFT/PBE0-D3 level of theory with all electron basis set (double zeta with polarization on light elements and triple zeta with polarization for Cu atoms) as implemented in Crystal14. The Cu atoms were antiferromagnetically coupled in the present simulations (bands corresponding to  and  electrons are identical). Slipped and inclined stacking of SURMOF-2 layers induces out-of-plane dispersion in band structure, due to increased van-der-Waals and preferable Coulomb interactions. Pictures of structures made with VESTA. We have calculated the corresponding electronic band structures for all three stackings of Cu-SURMOF-2 (see Figure ). While the in-plane bands are nearly dispersionless, the stacking induces dispersion in the out-of-plane directions ( to Z). The conduction band is formed by dispersionless single state in all cases, which corresponds to the Cu d-orbitals. On the other hand, the valence band is dominated by C p-orbitals of the organic linkers. The P2 or C2 systems exhibit heavy electrons throughout the Brillouin zone, similar as in P4. However, light holes emerge due to stacking-induced band dispersion in the direction perpendicular to the layers.