tween the closed and open states, similar to the intermediate state. However, it falls lower along the second tIC and is distinct from the previously established intermediate state. For each system with multiple MSMidentified states, we estimate the timescales of the transitions between them by discretizing our trajectories to calculate a mean-first passage time (see Methods). This is highly approximate, especially given that in many cases we do not have multiple transitions between states and/or transitions may be unidirectional. However, these are useful in providing at least order of magnitude estimates of the relevant timescales. Our estimates of timescales further support the idea that the intermediate state is a relatively short-lived state. In both the 4w59-butylbenzene system (Figure ) and 4w57-hexylbenzene system (Figure ) where we observe transitions between the closed and intermediate states, we estimate that the process of going from closed to intermediate is over an order of magnitude slower than going from intermediate to closed (Table ). However, for the 4w57-hexylbenzene system (Figure ) where we observe transitions between the intermediate and open states, we instead find that going from open to intermediate is about an order of magnitude faster than going from intermediate to open (Table ).