Two-step synthesis for polycrystalline bulk growth of a solid solution based on the CdGCP(2) ternary compound is reported. Transition metal Mn was used as a chemical partner for the solid solution of a new semiconductor material (Cd, Mn)GeP2, which shows ferromagnetic properties. X-ray diffraction revealed a chalcopyrite crystal structure with a small change in the lattice parameter due to the Mn-content. The elevated concentration of the transition d-element (509,6) leads to extraction of the MnP secondary phase. All the Mn-containing polycrystalline phases (Cd, Mn)GeP2 showed a classic magnetization dependence on temperature and a magnetic hysteresis loop up to room temperature. The Curie temperature of polycrystalline (Cd, Mn)GeP2 was measured as 310 K, which is slightly lower than that of the single crystal phase. (C) 2002 Elsevier Science B.V. All rights reserved.