Perturbation-induced FOs should be relevant in conductance studies of linear molecules. Indeed, the effect of single bonds mentioned above may also explain different conductance trends in cumulenes and polyynes. The former is known to become more conductive with a longer chain, 152 probably because of a decreas-ing HOMO-LUMO gap. Polyynes, on the other hand, show a decrease in conductance with longer chain sizes. This may reflect an increase in the number of single bonds in the chain that hinder delocalization and cooperatively dump any long-range charge oscillations.