The photoreduction of aromatic nitro compounds by alcohols is a well-known reaction; however, the first stages of its mechanism remain controversial. This study aims at characterizing the "primary" radicalar transients involved in this reaction by EPR spectroscopy. Laser flash photolysis (lambda = 266 nm) of nitrobenzene, 5-nitrouracil, p-nitroacetophenone, o-propylnitrobenzene, and 2-nitroresorcinol in ethylene glycol was followed by time-resolved EPR spectroscopy. In all reported TR-EPR spectra, except those obtained from the photolysis of 2-nitroresorcinol, the key intermediate N-hydroxy-arylnitroxide radicals (ArNO.OH, 1-4) could be identified unambiguously. In 2-nitroresorcinol, the radical anion (ArNO.O-, 5) and a a iminoxy radical (6) were observed, and a third radical (7) remains unidentified. These observations indicate that two radicalar mechanisms (by H. transfer and by electron transfer) are competing in the photoreduction mechanism. The attribution of the EPR spectra was helped by DFT calculations of the hyperfine coupling constants (hcc's).