In this work, we mainly focus on probing into the effects of atomic electronegativity on photo-induced hydrogen bond (i.e., O-HÁÁÁN) effects and excited state intramolecular proton transfer (ESIPT) processes for a novel fluorescent chemical probe ONIP derivatives (i.e., ONIP-O, ONIP-S, and ONIP-Se). First, insights into optimized structural geometries and related infrared vibrational spectra, we clarify that the hydrogen bond O-HÁÁÁN interaction could be strengthened via photoexcitation. Further, via predicting hydrogen bonding energy E HB , we quantificationally present that the S 1 -state hydrogen bonding strengthening behavior should be more distinct with lower atomic electronegativity. When it comes to vertical photo-induced excitation, the intramolecular charge transfer process happens and the charge redistribution plays roles in promoting ESIPT behavior. It is worth mentioning the energy gap between highest occupied molecular orbital and lowest unoccupied molecular orbital show that low atomic electronegativity should be more favorable to ESIPT process. Finally, based on the restricted optimization method, we construct the potential energy curves along with hydrogen bond wire for ONIP-O, ONIP-S, and ONIP-Se. By exploring the conformation of potential energy curves and potential energy barriers, we disclose the detailed atomic-electronegativity-controlled ESIPT dynamical behaviors for ONIP system.atomic electronegativity, charge redistribution, excited-state intramolecular proton transfer, hydrogen bond interaction, IR vibrational spectra | INTRODUCTIONConsidering that hydrogen bond effect plays the most important role in various branches of science, we cannot deny that hydrogen bond interaction has become an indispensable research topic in the field of science. [1][2][3] After decades of research and development, it is not difficult to find that many physical chemists and biologists have been able to basically clarify the hydrogen bonding in the ground state (S 0 ) through the continuous exploration of combining theory and experiment. Although it cannot be denied that hydrogen bond interactions get very complicated when they are excited via light, the changes in the interactions are often completely different from the