Nitroxides are a versatile class of stable free radicals that have long established themselves in a wide range of biological, environmental and material based applications. In comparison to other common free radicals, nitroxides are stable, kinetically persistent systems that can even be isolated and stored as inert compounds under the right conditions. The great stability of the nitroxide arises principally from the strong stabilization energy of the unpaired electron between the two hetero atoms. Equally, the overlap of a non-binding lone pair interacting with the unpaired electron generates a three electron, two-centre π bond. While stable towards other nitroxides, they still retain many of the interesting properties of other, more reactive free radicals; spin trapping of C, S and P radicals at near-diffusion controlled rates; paramagnetism and one electron redox reactions. This talk will delve into some of these properties more deeply and show some recent examples of nitroxide-containing materials as MRI contrast, fluorescent probe and cathode/catholyte materials.