3-Methyl-3H-imidazo[4,5-b]pyridine and 1-methyl-1H-imidazo[4,5-c]pyridine have been obtained in low yield from the thermolysis of 3-azido-2-dimethylamino- and 3-azido-4-dimethylamino-pyridine, respectively. Cyclisation onto the N-methylpiperazine ring failed. Low yields of imidazo[4,5-b]- and [4,5-c]pyridines have also been obtained from the oxidative cyclisation of aminopyridines with performic acid.