Abstract: A ferromagnetic organic substance having a triaryl methane structure and a free radical concentration of methine carbon positions of at least 10.sup.17 radicals/g, preferably at least 10.sup.18 radials/g, is provided by polycondensing a condensed polynuclear aromatic compound or an electron donating group substituted monocyclic aromatic compound with an aromatic aldehyde in the presence of an acid catalyst, to produce a precondensate having a softening point between 30.degree. C. and 120.degree. C. and being soluble in various organic solvents, and subjecting the resulting precondensate to a dehydrogenation treatment and a purification treatment, followed by molding.

Abstract: A thermosetting resin composition is disclosed which comprises a fusible product obtained by a method including the steps of:providing a mixture which comprises (a) a raw material containing one or more condensed polynuclear aromatic compounds having at least two condensed benzene rings, (b) a crosslinking agent containing an aromatic compound having one or more aldehyde groups directly bonded to the aromatic nuclei thereof, and (c) an acid catalyst; andreacting the mixture at a temperature sufficient to effect the crosslinking of the one or more condensed polynuclear aromatic compounds, thereby to obtain the fusible product. A further heat treatment of the thermosetting resin composition gives a COPNA resin which is an infusible, insoluble, condensed, polynuclear aromatic hydrocarbon resin.