The magnetic properties of poly(2-(3,5-diethynylenephenyl)-4,4,5,5-tetramethyl-4,5- di-hydro-H-1-imidazol-1-oxyl-3-oxide) (4), a polymer with conjugated backbone and stable radicals in side groups, were investigated between 78 and 300 K with magnetic flux densities B between 0.42 and 1.32 Tesla. Samples prepared by evaporation of the solvent from the polymer solution exhibited normal paramagnetism. Samples precipitated by addition of a nonsolvent (n-hexane) to a polymer solution showed a dependence of the magnetic mass susceptibility chi(m) on B. This behavior is described by superposition of a paramagnetic term and a temperature-independent term depending on B. In addition, an increase of chi(m)T With decreasing temperature T was observed below 150 K.