The design and fabrication of new nanostructures with controlled functionality, size, shape, and position are major goals in nanoscience. 1 The concept of self-assembly of molecular building blocks to generate well-defined architectures based on non-covalent interactions with the supporting substrate is technologically appealing. 2 Such intriguing supramolecular assemblies often possess polymeric characteristics and are referred to as ''supramolecular polymers''. 3 The generation of such organized structures, obtained by controlling supramolecular interactions, makes tuning of the physicochemical properties of these molecule based materials possible. In this context, to combine organic molecules with metal entities is particularly useful. 4,5 On the other hand, the bottom-up approach for forming on-surface nanostructures by direct sublimation of their building blocks under ultra-high vacuum conditions has been shown as an excellent approach to this goal. 6 However, this experimental approach presents a limitation coming from the stability that it is required for the molecule to allow sublimation without structural damage. This is the reason why there are a relatively high number of nanostructures based on organization of ideal organic molecules but few of them are based on the combination of organic molecules with metal fragments. 7 The metal-organic structures formed up to now by sublimation are almost limited to those simple cases obtained by sequential sublimation of both building blocks, organic molecules and metal precursors, or just by sublimation of the organic molecules and their subsequent in situ reaction with the metal atoms coming from the metallic surface. 8,9 In both cases the selection of the building blocks has allowed formation of a large variety of 1D-or 2D-coordination polymer architectures. [10][11][12] In most of the previous studies of large complex molecules on surfaces the molecules were transferred from a solution [13][14][15][16][17][18][19] or by a dry imprint technique 20 to the substrate in order to preserve the fragile core. In this communication we focus on the search of a new metal-organic complex with a robust structure able to be sublimated keeping its molecular integrity and to self-assemble without being disrupted by the surface. We have been able to directly sublimate under ultra-high vacuum (UHV) conditions a large metal-organic cluster that is, as far as we know, the largest molecular complex ever sublimated and in situ characterized by STM. This allows the formation of well-controlled nanoarchitectures readily on a surface and use of advanced surface in situ techniques. To achieve this goal, we combine in situ scanning tunnelling microscopy (STM), X-ray photoemission spectroscopy (XPS), and low energy electron diffraction (LEED) experiments with ab initio calculations.Recently, we have reported on the synthesis and characterization of a robust metal-organic cluster [Cu 4 (m 3 -Cl) 4 (m-pym 2 S 2 ) 4 ] (pym 2 S 2 = dipyrimidinedisulfide) (1) showing interesting physical and...