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Inspired by the complex molecular machines found in nature, chemists have developed much simpler molecular motors.[1–3] Among them, several systems incorporating azobenzene have been proposed, which exploit the reversible trans–cis isomerization triggered by light [4] or an electric field [5] for applications such as optical data-storage devices,[6] switchable supramolecular cavities, and sensors.[7] Recently, it has been demonstrated that the photoisomerization process of individual polymer chains incorporating azobenzenes can express mechanical work.[8] In light of these findings, one can foresee self-assembled monolayers (SAMs)[9, 10] of aromatic azobenzenes as molecular systems able to express forces of unprecedented magnitude by exploiting a collective subnanometer structural change. We recently designed a rigid and fully conjugated azobenzene exposing a thiol anchoring group,[11] which was able to form a tightly packed SAM on Au (111)(SAMAZO). Scanning tunneling microscopy (STM) studies revealed that upon light irradiation of the chemisorbed SAMs, a collective isomerization of entire molecular-crystalline domains occurred with an outstandingly high directionality.[11] Based on these results, a cooperative nature of the isomerization of adjacent AZO molecules has been proposed. Furthermore, the joint action of the molecules in the SAM provides an ideal system as a potential “cargo” lifter. Herein, we show that, upon irradiation, azobenzene SAMs incorporated in a junction between an Au (111) surface and a mercury drop are able to 1) lift the “heavy” Hg drop, and 2) reversibly photoswitch the current flowing …