The renewed interest in noncovalently associating electroactive molecules [1, 2] arises in part from the quest for new organic materials that convert solar energy into electrical/chemical equivalents.[3] In this context, the formation of charge-separated states is a key prerequisite. Charge-transfer events triggered by light have been studied in supramolecular donor–acceptor systems based on hydrogen bonds [1b, 2a, b] and coordinative metal bonds.[2c, d] Although many of the most widely utilized electroactive fragments feature large πconjugated surfaces, to date the use of π–π aromatic interactions [4] has mainly been limited to the construction of semi-infinite ensembles of chromophores either to achieve charge transport [5]—with the known example of charge transfer through DNA bases [6]—or to increase the efficiency of light absorption.[7] Detailed studies on charge-transfer interactions in discrete supramolecular systems held together by π–π aromatic interactions are surprisingly scarce.[8] Recently, we succeeded in the realization of donor–acceptor supramolecules based on the recognition of the convex exterior of C60 by the concave surface of π-extended tetrathiafulvalene derivatives.[9] Numerous incentives, especially in the context of constructing more efficient optoelectronic devices, are offered by these C60/exTTF materials. Herein we describe the physicochemical characterization of the supramolecular donor–acceptor π complexes and provide a theoretical description of the underlying host–guest interactions.

The meta and para tweezers (MTW and PTW, respectively) share a straightforward design, in which two 2-[9-(1, 3-dithiol-2-ylidene) anthracen-10 (9H)-ylidene]-1, 3-dithiole (exTTF) units are connected through isophthalic or terephthalic diester spacers, respectively (Scheme1). MTW and