Novel palladium(II) complexes (4-6) have been synthesized from the reaction of (E)-3{[(diethoxythiophosphoryl)-methylhydrazone]-methylene}-4-hydroxy-2H-1-benzopyran-2-one (1), E)-3-{[(dimethoxythiophosphoryl)-methylhydrazine]-methylidene}-3,4-dihydro-2H-1- benzopyran-2,4-dione (2) and (E)-3-{[(diethoxythiophosphoryl)-hydrazone]-methylene}- 4H-1-benzopyran-4-one (3), respectively, with PdCl2(PhC...