Another interesting observation of T 1 in TIPS-Pn is by Zirzlmeier et al., who reported the TA of a 0.3 mM solution of TIPS-Pn in Me-THF. 12 They noticed significant triplet formation over a 125 ns time window. As with Grieco et al., they assumed that there was no SF at 0.3 mM, and attributed the triplet formation to ISC, reporting an ISC time constant of 12.3 ns. This overly high ISC rate constant is at odds with other observations of dilute TIPS-Pn solutions in the literature, and corresponds to an ∼50% triplet yield over 100 ns (Table ). If we instead consider that SF can occur in this solution, and use k SF reported by Dvořák et al. (the viscosity of Me-THF is closer to chloroform than toluene), and the upper limit of k ISC found in this study, we still only predict 6.7% triplet formation in 100 ns (43% of this is from SF). It is possible that TIPS-Pn has lower solubility in Me-THF, and the triplets observed are due to faster SF in aggregates. ISC can also be affected by solvent polarity, but the solvatochromism in TIPS-Pn between toluene, chloroform and Me-THF is minor, so solvent should only have a weak effect on the ISC rate in these studies. Alternatively, the solubility of oxygen in Me-THF is higher than in toluene and chloroform. If the solution contained some oxygen, it is possible the triplet formation was a result of triplet sensitization by oxygen rather than SF or ISC. It has also been shown that oxygen can enhance triplet formation by acting as a catalyst for SF. The above are all cases where ISC appears to have been overestimated, or SF misassigned as ISC. This can be seen in Fig. , which shows the variation in relative significance of ISC and SF with TIPS-Pn concentration determined from the measurements in this study, compared with values from literature. It is also possible for ISC to be misassigned as SF, or triplet contributions due to ISC neglected, leading to an overestimation of SF rates or triplet yields. We show above that for 8 mM TIPS-Pn, including the effects of ISC modified the SF rate constant from