Chlorine radical (&middot;Cl) initiated oxidation of organic nitrogen compounds (ONCs) plays an important role in carcinogenic nitrosamines formation. Imines are important constituents of ONCs, primarily formed from the atmospheric oxidation of amines. However, ∙Cl-initiated atmospheric oxidation of imines remains poorly understood. Here, we studied the reaction mechanisms and kinetics of &middot;Cl-initiated oxidation for five representative imines (CH₂=NH, CH₃CH=NH, CH₃N=CH₂, (CH₃)₂C=NH, HN=CHCH₂OH) to elucidate their atmospheric fate and extend the limited available data of ONCs, thereby establishing a structure-activity relationship for the reactions. The calculated overall reaction rate constants (&times; 10^&ndash;11 cm³ molecule^&minus;1 s^&minus;1) of ∙Cl + CH₂=NH, ∙Cl + CH₃CH=NH, ∙Cl + CH₃N=CH₂, ∙Cl + (CH₃)₂C=NH, and ∙Cl + HN=CHCH₂OH are 4.5, 27.2, 7.32, 44.8 and 12.6, respectively, which are consistent with the available experimental values. Importantly, our results show that the ∙Cl-initiated reactions of the NH-containing imines mainly produce N-centered radicals. These N-centered radicals exhibit various fates under tropospheric conditions: mainly reacting with NO to form nitrosamines or with O₂ to form cyanide compounds, which differs substantially from the behavior of previously reported amines. The various fates of the N-centered radicals formed from imines originates from the difference in direct hydrogen abstraction reaction rate constants (<em>k</em>_O2) with O₂ and the reaction rate (<em>k</em>_NO) with NO, both of which are<span> </span>principally governed by the distinct molecular structure of N-centered radicals. The revealed reaction mechanism provides new insights into the atmospheric transformation and risks of imines, and enrich our understanding of ∙Cl/ONCs chemistry.