Novel antineoplastic agents comprising mono-nuclear transition metal complexes. The said complexes contain a tetrapyrido[3,2-a:2,3-c:3",2"-h:2â ,3--j] phenazine (tpphz) ligand and have dual functioning imaging/therapeutic properties. Also described is their use in photodynamic therapy and as chemotherapeutic agents. The cytotoxicity of these complexes is comparable to that of platinum-based chemotherapeutics, especially for platinum-resistant tumour cells. Preferred transition metals include Ru (II), Os (II) or Ir (III), preferably Ru (II).
