New complex phosphates of the general formula K 2 M 0.5 Ti 1.5 (PO 4 ) 3 (M=Mn, Co) have been obtained from the melting mixture of KPO 3 , K 4 P 2 O 7 , TiO 2 and CoCO 3 ·mCo(OH) 2 or Mn(H 2 PO 4 ) 2 by means of a flux technique. The synthesized phosphates have been characterized by the single-crystal X-ray diffraction and the FTIR-spectroscopy. The compounds crystallize in the cubic system with the space group P2 1 3 and cell parameters a=9.9030(14)Å for K 2 Mn 0.5 Ti 1.5 (PO 4 ) 3 and a=9.8445(12)Å for K 2 Co 0.5 Ti 1.5 (PO 4 ) 3 . Both phosphates are isostructural with the langbeinite mineral and contain four formula unit K 2 M 0.5 Ti 1.5 (PO 4 ) 3 per unit cell. The structure can be described using [M 2 (PO 4 ) 3 ] framework composed of two [MO 6 ] octahedra interlinked via three [PO 4 ] tetrahedra. The Curie–Weiss-type behavior is observed in the magnetic susceptibility.