An efficient, one-pot approach has been established for synthesizing a wide range of 3-amino-[1,2,4]-triazolo pyridines and related heterocycles from the electrochemically induced desulfurative cyclization of 2-hydrazinopyridines with isothiocyanates. The protocol allows for the formation of C-N bonds under simple conditions without transition metals or external oxidants. The practicability of this strategy is demonstrated by its broad substrate scope, good functional group compatibility, and gram-scale synthesis. The late-stage modification of 3-amino-[1,2,4]-triazolo pyridines enables us to obtain several molecules with potent anticancer activity.