As the molecules form trimers, the electron delocalization is expected to increase further and thus the gap to shrink accordingly. That is indeed the case. For the hexamethyl [10]-starphene t1, taking the dimer d2 as reference, the LUMO remains hardly unchanged at 1.64 eV. However, the HOMO level shifts upward to 0.94 eV and thus closes the semiconducting gap to 2.58 eV. Also here the conductance maps at the HOMO and LUMO energy agree nicely with density functional theory calculations (Fig. ), keeping in mind that the main discrepancies relate, as in the case of the dimers, to the deviations from planarity as the molecules adsorb on the Au(111) surface. That is, the highest position of the methyl groups and the concomitant increase in height of the nearest sp 2 carbon atoms cause the DOS lobes on the latter to appear strongest, as well as the appearance of additional unexpectedly strong lobes at the positions of the former (Fig. ). The calculated wavefunctions of HOMO and LUMO on each of the arms of t1 look extremely similar to those of m1 (Fig. ). However, the conjugation and electronic coupling between the arms becomes evident from the decreased gap, which implies a substantial electron delocalization over the whole structure. It is interesting to compare the symmetric t1 molecule with the asymmetric t2 molecule. Although both are closely related, in the case of t2, theory predicts the HOMO and HOMO-1 to be quasi-degenerate, and the same applies to the LUMO and LUMO+1. Indeed, their superposition provides a substantially better match to the experimentally measured conductance maps at the energies of the frontier orbitals (Fig. ) than if compared to HOMO and LUMO alone (Fig. ). Nevertheless, the experimentally observed gap of t2 is, within our experimental resolution, equal to that of t1.