The pyrimidinodithiocarbamate polymer was prepared from the reaction of 2-mercapto-4,6-diaminopyrimidine with carbon disulfide, followed by condensation through the removal of H2S gas. Three polymer–metal complexes of cobalt, nickel, and copper were then prepared. The polymer and its complexes were investigated by elemental analyses, UV, IR, and magnetic susceptibility. The DC electrical conductivity variation, with the temperature in the region 298–498 K, of the polymer in its undoped and doped (5% iodine and 5% NiCl2) states and, also, of the three polymer complexes was determined. All the complexes showed an increase in conductivity with an increase in temperature in a semiconductor behavior. The thermal stability of the complexes was studied using the TGA technique. The structures of the polymer and its complexes were assigned. The proposed structure of the complexes is (MLX2.mH2O)n. All the polymer complexes are thermally stable, are insoluble in common organic solvents, and have high melting points.