[Fe(terpy) 2 ] 2+ is a member of the family of Fe(II) polypyridines, which are known to undergo a light-induced spin transition from the singlet GS to the metastable quintet MC state within a few hundred fs . However, the mechanism of the photoswitching as proposed by time-resolved experiments has been controversial and thus has debated over a decade whether the 5 MC state is populated directly from the 3 MLCT manifold or sequentially, i.e., 3 MLCT → 3 MC → 5 MC. Recently, we clarified the excited-state mechanism of Fe(II) polypyridines by simulating the excited-state dyanmics of [Fe(terpy) 2 ] 2+ using full-dimensional TSH simulations carried out on PESs calculated by B3LYP*-LVC. We note that shortly afterwards, two papers on the [Fe(bipy) 3 ] 2+ complex were published (bipy = 2,2'-bipyridine), reporting ultrafast dynamics simulated by full-dimensional TSH 66 and reduced-dimensional quantum dynamics. Importantly, all three dynamics studies consistently identify the sequential mechanism being the dominant one.