[en] Reaction of one mole of acetylacetone with two moles of 4-phenylthiosemicarbazide yields the unusual Schiff base, MeC(=N-NHCSNHPh)CH₂C(=NNHCSNHPh)Me, APT=H₂L) acetylacetone bis(4-phenylthiosemicarbazone). The complexes of Co(II), Ni(II), Cu(II), Zn(II) and U(VI)O₂ have been prepared and characterized by analytical, i.r., electronic spectral and magnetic measurements. The Co(II), Ni(II) and Cu(II) complexes have been assigned square-planar stereochemistry on the basis of magnetic and spectroscopic studies. The ligand is a neutral or dibasic quadridentate SNNS donor as revealed by i.r. spectral studies. (orig.)