The invention comprises a chemical composition with the structure shown below. The composition can be polymerized or pyrolyzed, forming transition metal nanoparticles homogeneously dispersed in a thermoset or carbon composition. The size of the nanoparticles can be controlled by manipulating the number and arrangement of functional groups in the composition and by changing the conditions of the polymerization or pyrolysis. The resulting thermosets and carbon compositions have useful magnetic, electric, mechanical, catalytic and/or optical properties. ##STR00001## wherein A is selected from the group consisting of H, ##STR00002## wherein M is a metal selected independently from the group consisting of Fe, Mn, Ru, Co, Ni, Cr and V; wherein Rx is independently selected from the group consisting of an aromatic, a substituted aromatic group and combinations thereof; wherein Ry is independently selected from the group consisting of an aromatic, a substituted aromatic group and combinations thereof; wherein m is .gtoreq.0; wherein s is .gtoreq.0; wherein z is .gtoreq.0; and wherein m and s are independently determined in each repeating unit.