Congratulations to Mei on the acceptance of her paper “Solvent-Controlled Product Branching in Riboflavin Uncovered by Time-Resolved Infrared and Transient Absorption Spectroscopy” in the Journal of Physical Chemistry Letters. The manuscript determines the entire photocycle of Riboflavin (Vitamin B₂), and the factors that govern the relative yields of its singlet and triplet excited states- both playing important roles in electron transfer chemistry. The photoexcited states are tracked over 9 decades of time using both transient absorption and time-resolved infrared spectroscopy. By changing the solvent from DMSO to water, the triplet quantum yield increases by a factor of 2.7, but not due to an enhancement in spin-orbit coupling. Instead altered hydrogen bonding changes the rate of internal conversion. The study also serves as a demonstration of our new experimental capabilities of following photoinduced reactions from femtosecond to millisecond timescales.