Various new 2-substituted 4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-yloxyl 3-oxide mono- 1b, 7, 13a,b, 14, 15, 16, 17, 22 and biradicals 8, 9 were prepared. The nitronyl nitroxide functions were selectively reduced by Fe/HOAc to 1-hydroxyimidazoline derivatives 3b, 11, 21. The reductions by Zn/HCl led to imidazolines 4, 12. The nitronyl nitroxide functions remained inert when the 2-phenyl compound was nitrated by H2SO4/HNO3 to give nitrophenyl nitronyl nitroxide derivatives 13a,b, 14.