Recent results of magnetization, susceptibility and muon spin rotation (mu SR) measurements and crystal structure determinations of the organic radicals based on cl-nitronyl nitroxide are described. Temperature variation of mu SR 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 similar to 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.