1,2-dihydrobenzo[e][1,2,4]triazine is a important class of heterocycles,which exists widely in natural products.Many compounds containing those motifs exhibit potent biological activities and medicinal significance.Herein we developed a highly efficient I2 promoted domino protocol for the diverse synthesis of highly substituted 1,2-dihydrobenzo[e][1,2,4]triazines from simple and readily available aryl methyl ketones and N-(2-aminophenyl)benzohydrazides.In our reaction,three mechanism-different reactions(iodination,[1] Kornblum oxidation,[2] and heterocyclization)were assembled in a single reactor.[3-5] Hydrazine hydrate could be used as nucleophilic agent to attack the carbonyl group of product A to produce another product B,which underwent a deacylation process.[6] It is notable that the reaction performs well with varying functional group tolerance in the absence of any metal,base,or ligand.Due to the above mentioned characteristics of this reaction,it should be of great utility for concise construction of diverse heterocycles for organic chemistry and medicinal chemistry.