In 1972, Burr et al. presented experimental evidence that the Cyd photohydrates are not formed from the fluorescence excited singlet state or the triplet excited state but likely from a 1 n* excited state or a singlet excited water-Cyd complex. Recently, Szabla and coworkers 41 investigate the formation of the 6hydroxycytidine and other photoproducts computationally using cytosine (C) and 1-methylcytosine (1mC) complexed with two explicit water molecules at the CC2 and MR-CISD levels of theory. The authors concluded that a 1 n* state primarily associated with a n N molecular orbital and characterized by pronounced water-to-C or water-to-1mC charge transfer and a strong water-N3 interaction, can give rise to the formation of 6-hydroxycytidine, oxazolidinone, and -uridine photoproducts. The experimental and computational results by Burr and Szabla lend further support to our proposal that the 1 n N * excited state give rise to the formation of 6-hydroxycytidine and likely to others of the primary photoproducts of Cyd (and conceivably in 5mCyd) in aqueous solution, possibly through the reaction mechanism described Szabla and coworkers. See, Figures and, and associated discussion in their paper. To further supports the idea that 6-hydroxycytidine and other primary photoproducts are formed from an 1 n N * excited state reacting with a water molecule, Figure presents the changes in the absorption spectra for 5mCyd and Cyd following low intensity laser irradiation at 267 nm in dry (< 0.01% water) acetonitrile at ambient conditions. The corresponding photodegradation rates are also reported in panel (c). The photoreactivity of both 5mCyd and Cyd decreases by two to three orders of magnitude relative to the experiments performed in aqueous solution. This observation strongly support the idea that water molecules play a key role in the formation of the main photoproducts, as proposed above and predicted by quantum chemical calculations. and Todd et al. Unfortunately, the experimental absorption spectrum of 𝛽-dribocytidine-2',3'-cyclic phosphate is not reported by the authors. The agreement of the experimental spectra of the photoproducts eluting at 4.96 and 5.48 min (recorded at pH 5.6 and with the HPLC photodiode array detector) with the calculated spectrum is reasonable, particularly for the photoproduct eluting at 4.96 min. However, we remark that more experimental and computational work is necessary to characterize these photoproducts unequivocally.