Again, SF is generally thought to be faster, and should result in a triplet yield (per singlet exciton) greater than 100%, whereas ISC is slower, and should give a triplet yield less than 100%. However, determining yields of triplets can be complex, and triplet production can easily be over-or underestimated. Additionally, SF is not always completely efficient, and can occur with a yield below 100%. Finally, SF, particularly in solution and in disordered solid-state systems is not necessarily always fast. A recent study by Dvořák et al. showed that SF in TIPS-Pn solutions occurs by diffusive encounters, and so can be very slow in dilute solutions. SF has also been shown to be limited by exciton diffusion to SF-favorable sites in disordered acenes, and so can be considerably slow in disordered solids or systems with substantial singlet migration. In this study, we show that SF can be misidentified as ISC and vice versa, and demonstrate the need to take precaution in the assignment and interpretation of photophysical processes in SF-capable systems, particularly using optical spectroscopy. We focus on two commonly studied SF chromophores: 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-Pn) and 5,12-bis(triisopropylsilylethynyl) tetracene (TIPS-Tn).