Stable nitroxide radicals with rigid core were used as spin probes for investigation of orientational order of nematic liquid crystals MBBA and 5CB, uniaxially stretched polyethylene and porous polyethylene. The orientation distribution functions of probe molecules were determined. The order parameters of the true orientation axes were estimated. It was demonstrated that the novel nitroxide radicals show orientational alignment of both liquid crystals and polymers more effectively than ordinary spin probes.