Since each molecular row within the self-assembled island starts and ends with a rounded feature and taking into consideration the observed periodicity and the fact that it is not expected that the BOPHY molecule decomposes at 370 K, we propose the molecular model superimposed to the STM image in Figure , corresponding to a (Au-BOPHY)n chain. This model, based on hybrid metal-organic chains on the Au(111) surface, assigns the center of the elongated feature to a gold surface adatom and fits perfectly with the characteristics observed when a defect is detected (see the molecular vacancy in the middle of the second upper molecular row). In that case, a rounded/elongated/rounded group is observed on both sides of the defect, which corresponds to a fully dehalogenated metal-organic dimer. This result indicates that the formation of BOPHY-based metal-organic oligomers originates by the thermal dehalogenation of the pristine molecules. Although one might expect the Ullmann reaction to occur by thermal activation, with the corresponding formation of a C-C covalent coupling between BOPHY molecules, that process does not take place, as inferred from the distance between chain slabs. The reason resides on the presence of the four voluminous terminal methyl groups, which prevent the formation of the C-C bond due to steric effects. On the other hand, the small rounded features of the lower part of Figure (red circles) are characteristic of atomic iodine, also present in the porous network surrounding the self-assembled islands, which is hardly distinguished in Figure and better discerned in Figure . These atoms, that after dehalogenation no longer bind to BOPHY molecules, remain on the surface forming a pseudo-hexagonal network on Au (111), as previously reported in the literature . Figure represents the corresponding F 1s, I 3d and C 1s XPS spectra. The F 1s signal does not change with respect to that of the RT phase, indicating that the fluorine atoms remain intact on the molecular backbone. This is not surprising, as it has been reported that F atoms remain attached to carbon-based molecular backbones at this temperature on Au(111) , and the C6H5-F bond is weaker than the BF-F bond present in BOPHYs (485 kJ/mol vs 523 kJ/mol) . However, in the I 3d emission, the peak at 620.6 eV, associated to C-I, disappears, while only the peak at 619.3 eV, characteristic of chemisorbed I on the surface, remains, indicating the complete molecular dehalogenation. On the other hand, the C 1s XPS spectrum shows the vanishing of the C-I emission at 284.9 eV together with the development of a new component at 283.2 eV, typically assigned to C-metal bonds . These XPS results confirm our previous hypothesis based on the STM images and evidence that, in the case of Au(111), the thermal treatment at 370 K leads to the complete dehalogenation of the I-BOPHY-I molecules and the formation of hybrid metal-organic chains.