Tetrazolo [1, 5-a] pyridines may be prepared by the reaction of azide ion with 2- chloropyridines. These tetrazolo [l, 5-a] pyridines are shown to be in equilibrium with the corresponding 2-azidopyridines. Furazano [4, 5-blpyridine 1-oxides may be prepared by thermolysis of the appropriate 4-nitrotetrazolo [l, 2-a] pyridines, presumably via the corresponding 2-azido-3-nitropyridines. The furazano [4, 5-b] pyridine 1-oxides are found ...