Reaction of the deprotonated N-thiophosphorylated thioureas o-RO(O)CC₆H₄NHC(S)NHP(S)(OiPr)₂ (R = Me, HL^I; Et, HL^II) with CuI and AgNO₃ leads to the homoleptic polynuclear complexes [Cu₃L^I,II₃], [Ag₄L^I₄] and [Ag₅L^II₅]. The crystal structures of the former three complexes were determined by single-crystal X-ray diffraction. The nuclearity of the latter complex was established by the reaction with 1,10-phenanthroline (phen) with the exclusive formation of the heteroleptic mononuclear complex [Ag(phen)L^IIII]. The same mixed-ligand complex was also obtained by the reaction of KL^IIII with a mixture of CuI and phen. The complex [Ag₅L^II₅] is the first example of a homoleptic polynuclear Ag^I complex with RC(S)NHP(S)R′₂ exhibiting a pentanuclear structure.