Hydrogen evolution reaction (HER) and hydrogen oxidation reaction (HOR) are fundamentally and practically important in electrochemistry. However, the sluggish kinetics of HER/HOR in alkaline solution remains ambiguous and has been under extensive debate1. Most recently, Snyder’s and Tang’s groups2 reported that caffeine can significantly enhance both the HER and HOR kinetics of all Pt surfaces in alkaline solutions. However, the underlying mechanism for the caffeine-induced HER/HOR improvement of Pt in alkaline remains unexplained. In this work, we tend to resolve this puzzle by modulating the HER/HOR kinetics of Pt in alkaline by adding a variety of organic compounds in alkaline solutions, and probing how these organic compounds react with the Pt surface and tune the interfacial environment via advanced electrochemical characterizations and in situ spectroscopic techniques. We found that the organic compounds are non-specifically adsorbed on the Pt surface during the HER/HOR, and thus their induced HER/HOR improvement of Pt in alkaline cannot be accounted for by the hydrogen binding energy theory and bifunctional mechanism. We alternatively argue that the organic compounds improve the HER/HOR kinetics of Pt in alkaline by reorienting the interfacial water to facilitate the Volmer step, which refines our previous argument that interfacial water improves the HER/HOR kinetics of Pt via shuffling the reaction intermediates such as Had and OHad throughout the interface3. Acknowledgement This work was supported by the Office of Naval Research (ONR) under award number N00014-18-1-2155. This research used beamline 8-ID (ISS) of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704. Liu, E.; Li, J.; Jiao, L.; Doan, H. T. T.; Liu, Z.; Zhao, Z.; Huang, Y.; Abraham, K. M.; Mukerjee, S.; Jia, Q., Journal of the American Chemical Society 2019, 141 (7), 3232. Intikhab, S.; Rebollar, L.; Li, Y.; Pai, R.; Kalra, V.; Tang, M. H.; Snyder, J. D., ACS Catalysis 2020, 10 (12), 6798. Liu, E.; Jiao, L.; Li, J.; Stracensky, T.; Sun, Q.; Mukerjee, S.; Jia, Q., Energy & Environmental Science 2020, 13 (9), 3064.