It was also found that the contribution of optically allowed CT states to the excited state wavefunctions varies greatly with bridge connectivity and represents the determining factor for the singlet fission rate constant. In T-26N-T (Figure ) for example, the most dominant term in the wavefunction that contributes to the optical transition at ~3.5 eV is from a 𝐶𝑇 ## configuration involving direct CT between the terminal tetracene molecules (Figure ).