Recent results of magnetization, susceptibility and muon spin rotation (μSR) measurements and crystal structure determinations of the organic radicals based on α-nitronyl nitroxide are described. Temperasture variation of μpSR and a.c. susceptibility reveals that the organic radicals, which are found to exhibit ferromagnetic intermolecular interactions, undergo magnetic phase transitions at around 0.1-0.7 K. The organic radicals have not only a simply ferromagnetic ordered state but also canted spin magnetic orders. Microscopic views of the magnetically ordered states in the organic radicals are discussed by taking account of the molecular arrangements in the crystals.