Probing Ultrastrong Through‐Space Electronic Coupling in Donor‐Acceptor Systems at the Single‐Molecule Level

ABSTRACT Through‐space donor‐acceptor (TSDA) interactions have recently emerged as a new paradigm for charge transfer and transport in organic semiconductors. However, the intrinsic D–A coupling strength and charge transport properties at the molecular level remain unexplored in comparison to established through‐bond channels. Here, we employ a variety of single‐molecule techniques to directly probe TSDA charge transport characteristics in a series of strategically designed face‐to‐face D–A systems, revealing that optimized spatial proximity and electronic complementarity yield conductance values up to ∼0.19 G 0 , comparable to the best‐performing through‐bond molecular wires. Flicker noise analysis, current‐voltage characterization, and mechanical stretching measurements confirm robust electronic and mechanical coupling, while theoretical calculations and photophysical studies identify through‐space transmission as the prevailing mechanism. These findings establish non‐covalent TSDA coupling as an efficient charge‐transport channel and provide new molecular‐level insight for the design of D–A systems in organic electronics and optoelectronics.