Abstract: The invention provides a method of manufacturing polyaniline having magnetic properties and improved non-linear electrical properties, starting from neutral polyaniline, the method comprising the following steps: the neutral polyaniline is dissolved at a concentration of 0.1 to 3 parts per hundred by weight in a solution of fuming sulfuric acid including, at a concentration lying in the range 0.1 to 10 parts per hundred by weight, a magnetic metal, a magnetic metal salt, or any mixture of such metals and/or metal salts that is soluble in fuming sulfuric acid; the solution is maintained under stirring for a length of time lying in the range 10 minutes to 72 hours; the solution is poured slowly into methanol or distilled water to obtain a precipitate of magnetic self-doped polyaniline; and the precipitation cake is washed until the washing solution has neutral pH, and said precipitation cake is dried.