“…An in-depth knowledge of the electronic absorption spectra and the evolution of the recorded features with the oxidation state is particularly important for the characterization of the system. Indeed, the UV/Vis spectrum is employed, for instance, as a fingerprint of the oxidation state of the TCNE unit, [5] as a useful tool to determine the structure and the nature of the CT complexes in which this molecule participates, [6] to detect the formation of dimers, [7,8] or to analyze photoinduced electrontransfer processes in molecular complexes. [9] Furthermore, three major open questions concerning the excited states of [TCNE] À need to be clarified : 1) what is the assignment of the band detected around 5.5-5.8 eV in the UV/ Vis spectrum of this system?…”