Cyclization of thiosemicarbazones derived from β-keto esters and β-keto amides (HTSC) in the presence of diphenyllead(IV) acetate was explored in methanol solution at room temperature and under reflux. All β-keto ester TSCs underwent cyclization to give the corresponding pyrazolone (HL), which, except in one case, deprotonated and coordinated the PbPh 2 2+ moiety to form homoleptic [PbPh 2 (L) 2 ] or heteroleptic [PbPh 2 (OAc)(L)] derivatives. Cyclization did not occur with β-keto amide TSCs and only [PbPh 2 (TSC) 2 ] or [PbPh 2 (OAc)(TSC)] thiosemicarbazonates were isolated. The complexes were characterized by IR spectroscopy in the solid state and by 1 H, 13 C and 207 Pb NMR spectroscopy in DMSO–d 6 solution, in which they evolve and decompose with time. Additionally, crystals of p-acetoacetanisidide thiosemicarbazone (HTSC 10 ), [PbPh 2 (OAc)(L 5 )]·MeOH (HL 5 =2,5-dihydro-3,4-dimethyl-5-oxo-1H-pyrazolone-1-carbothioamide), [PbPh 2 Cl(L 2 )] (HL 2 =2,5-dihydro-5-oxo-3-phenyl-1H-pyrazolone-1-carbothioamide), [PbPh 2 (OAc)(TSC 8 )]·2MeOH (HTSC 8 =acetoacetanilide thiosemicarbazone), [PbPh 2 (OAc)(TSC 10 )]·H 2 O and [PbPh 2 (OAc)(TSC 11 )]·0.75MeOH (HTSC 11 =o-acetoacetotoluidide) were studied by X-ray crystallography. The complexes, monomers or dimers with almost linear C–Pb–C moieties, are compared with the corresponding derivatives of Pb(II).