Solar energy is essential if an ever-increasing demand for 2 energy is to be satisfied. While abundant, the solar radiation 3 reaching the earth's surface covers a broad range of 4 energies, from high-energy ultraviolet, through the visible 5 region, to low-energy infrared. 1,2 Efficient solar energy 6 capture and conversion are, therefore, challenging. For 7 photons with energies well-above the band-gap of the 8 absorbing material, excess energy is lost predominantly as 9 heat. In contrast, photons with energies below the optical 10 band-gap are not absorbed at all. Therefore, single-11 junction solar cells are limited to a maximum performance 12 of 33% known as the detailed balance limit. Both down- excitons after the absorption of a high-energy photon. 9,11, SF is spin-allowed and fast, as the correlated triplet pair use in, for example, photovoltaics. Conversely, materials 82 that feature isoergic or slightly endergonic SF, such as 83 tetracene, are suitable for emerging applications. Notably, if SF is isoergic, dissociation of the correlated 85 triplet pair into free triplet excited states may be hindered 86 by thermally activated triplet-triplet annihilation up-87 conversion (TTA-UC), a competitive process that yields a 88 higher-lying singlet excited state. TTA-UC is the reverse process to SF and involves the 90 fusion of two low-energy triplet excited states to provide 91 one high-energy singlet excited state. For TTA-UC to 92 occur, the energy of the singlet excited state of the 93 annihilator must be lower than twice the energy of the 94 triplet excited state. Based on this parameter, polycyclic 95 aromatic hydrocarbons, including anthracene, 96 tetracene, perylene, 58,59,60 and their derivatives have process. For dimers, the fate of 1 (T1T1) is governed by the 111 electronic coupling between the two chromophores. Control over the coupling is realized by different spacer 113 motifs. In strongly coupled dimers, 1 (T1T1)-5 (T1T1) mixing is Acenes -such as anthracene, tetracene, pentacene -and their derivatives are widely used as building blocks to probe multiexcitonic processes like SF and TTA-UC. In anthracene and pentacene, the energy of (S1) is lower or higher than twice the energy of (T1), respectively, which renders them suitable for the individual investigation of either TTA-UC or SF, respectively. In contrast, the (S1) energy of tetracene is close to twice the energy of (T1), and both SF and TTA-UC are thermodynamically feasible. Previous investigations have documented that tetracene is indeed capable of undergoing inter-and intramolecular SF and TTA-UC. To the best of our knowledge, however, studies regarding the interplay between SF and TTA-UC remain rare. To unravel the interplay between SF and TTA-UC, rigidly linked tetracene dimers are a promising platform as they allow for the control of electronic coupling by synthetic design. In analogy to our previous work on intra-SF in pentacene dimers, and AdTc, confirming the intramolecular nature of TTA-UC.