The singlet features decrease in amplitude concurrent with the formation of this peak, as shown in Fig. 1(d). This additional peak is consistent with the ESA of a TIPS-Pn triplet exciton. ISC is a unimolecular process, and so it should cause the same amount of triplet formation at 0.05 mM as at 8 mM. Given negligible triplet formation was observed at 0.05 mM, the triplet formation observed at 8 mM must be due to SF. TA gives no indication of spin coherence, and so potentially the 504 nm peak could be assigned to the 1 (T...T) state. However, since this state behaves spectroscopically the same as free triplets, for simplicity we refer to it as the T 1 state.