To test this hypothesis, we developed an analytical model based on Langmuir adsorption with a weakly bound conformation (low G state) that converts to a strongly bound state (high G state) (Supplementary Information, Section S.5). Here, the low G state corresponds to an upright molecular conformation with a junction anchored at both termini to metal electrodes, whereas the high G state corresponds to a molecular conformation in which a molecule is 'laying down' on the electrode surface via side chain-mediated van der Waals interactions. The concentration-dependent conductance behavior of the high G state suggests that molecular junctions transition from a 'standing up' to a 'laying down' conformation facilitated by intermolecular interactions between free molecules in solution and molecules linked to the surface electrode via a terminal anchor, thereby planarizing the terphenyl backbone and reducing steric hindrance for the adsorbed molecule to lay down on the surface. The sequential two-state adsorption results in a threshold-level dependence of solution concentration for the 'laying down' conformation (Supplementary Fig. ). As solution concentration is increased, the 'laying down' conformation becomes increasingly dominant, and the molecular sub-population exhibiting the high G state conductance increases. Overall, the results from the analytical model qualitatively agree with the concentrationdependent conductance behavior observed in experiments.