A series of highly soluble fullerene derivatives with varying acceptor strengths (i.e., first reduction potentials) was synthesized and used as electron acceptors in plastic solar cells. These fullerene derivatives, methanofullerene [6,6]‐phenyl C61‐butyric acid methyl ester (PCBM), a new azafulleroid, and a ketolactam quasifullerene, show a variation of almost 200 mV in their first reduction potential. The open circuit voltage of the corresponding devices was found to correlate directly with the acceptor strength of the fullerenes, whereas it was rather insensitive to variations of the work function of the negative electrode. These observations are discussed within the concept of Fermi level pinning between fullerenes and metals via surface charges.

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The covalent connection of the electron acceptor C 60 to p-quinonoid pi-extended tetrathiafulvalenes (exTTFs) has allowed for the preparation of new photo- and electroactive conjugates able to act as artificial photosynthetic systems and active molecular materials in organic photovoltaics. The gain of aromaticity undergone by the pi-extended TTF unit in the oxidation process results in highly stabilized radical ion pairs, namely, C 60 (*-)/exTTF (*+). Lifetimes for such charge-separated states, ranging from a few nanoseconds to hundreds of microseconds, have been achieved by rationally modifying the nature of the chemical spacers. These long-lived radical pairs are called to play an important role for the conversion of sunlight into chemical or electrical power.

Pathway complexity, hierarchical organization, out of equilibrium, and metastable or kinetically trapped species are common terms widely used in recent, high‐quality publications in the field of supramolecular polymers. Often, the terminologies used to describe the different self‐assembly pathways, the species involved, as well as their relationship and relative stability are not trivial. Different terms and classifications are commonly found in the literature, however, in many cases, without clear definitions or guidelines on how to use them and how to determine them experimentally. The aim of this Minireview is to classify, differentiate, and correlate the existing concepts with the help of recent literature reports to provide the reader with a general insight into thermodynamic and kinetic aspects of complex supramolecular polymerization processes. A good comprehension of these terms and concepts should contribute to the development of new complex, functional materials.

The first exTTF-based receptor for molecular recognition of fullerene is described. Unexpectedly, the receptor shows completely different binding modes in chlorobenzene and CHCl3/CS2 mixtures. In the aromatic solvent, the receptor binds C60 in a noncooperative fashion (nH = 1) with a Kassoc = (2.98 +/- 0.12) x 103 M-1, whereas in CHCl3/CS2 mixtures, it shows a marked positive homotropic cooperative effect (nH = 2.7) toward binding of C60, with an apparent binding constant of (3.56 +/- 0.16) x 103 M-1. The unique solvent-switchable behavior of our receptor might find use in the controlled self-assembly of exTTF-C60 donor-acceptor ensembles.