Abstract: The authors communicate their synthesis of poly(2,2,6,6 - tetramethyl - 4 -oxy -piperidyl - 1 - oxyl) butadiin (polySIPO ) and then their findings on the chemical composition and physical properties of polySIPO and its monomer as determined by IR,ESR,and ultimate analysis.The static magnetic susceptibility and the magnetization of polySIPO and SIPO were measured on an extracting sample magnetometer. It has been shown that SIPO shows paramagnetism but its polymer (polySIPO ) displays ferromagnetism. Ferromagnetism due to transition metal impurities can be ruled out by atomic absorption spectrometry and by contrasting the magnetism of polySIPO and SIPO.