Whereas BDA binds to a single gold atom at both atop-site and FCC-site electrodes, BDT binds differently to a FCC site than to an atop site, leading to different tunneling barrier heights at the two types of binding sites. The dissociation of the hydrogen atoms from the thiol groups and covalent binding of sulphur to the FCC hollow raises the transport level closer to the Fermi level and results in a lower φ b of 1.51 eV compared to 1.66 eV for the BDTgold-atop junction. Consequently, the conductance of the BDTgold-FCC junction (9.80 mG 0 ) is approximately double that of the BDT-gold-atop junction (4.33 mG 0 ) and also surpasses the conductance of the BDA-gold-FCC junction (7.87 mG 0 ).