It has been shown that 4-methylthio-, ethoxy-, and methoxyimidazotriazines and imidazotriazin-4-ones, unlike benzo-1,2,3-triazines, do not display cryptodiazonium behavior. A novel type of fission of the triazine ring to give esters and thioesters of 5-aminoimidazole-4-carboxylic acid is described.