The reactivity of the phosphinito bridged Pt(I) complex [(PHCy₂)Pt¹(μ-PCy₂){κ²P,O-μ-P(O)Cy₂}Pt²(PHCy₂)](Pt–Pt) (1) towards Au(I) and Ag(I) electrophiles was explored. Treatment of 1 with AuCl yielded the dichloro Pt(II) complex [(Cl)(PHCy₂)Pt(μ-PCy₂){κ²P,O-μ-P(O)Cy₂}Pt(Cl)(PHCy₂)] (4), while [Au(PPh₃)Cl] in thf (or toluene) caused ligand exchange resulting in the formation of [(PPh₃)Pt(μ-PCy₂){κ²P,O-μ-P(O)Cy₂}Pt(PHCy₂)](Pt–Pt) (7) and [(PPh₃)Pt(μ-PCy₂){κ²P,O-μ-P(O)Cy₂}Pt(PPh₃)](Pt–Pt) (8). With [Au(PPh₃)OTf] (independently from the solvent) or with [Au(PPh₃)Cl] (only in dichloromethane), reaction with 1 gave [(PHCy₂)Pt¹(μ-PCy₂){κ²P,O-μ-P(O)Cy₂}Pt²{μ-Au(PPh₃)}(PHCy₂)]X(Pt–Pt) ([6]X, X = OTf, Cl) clusters in which the [Au(PPh₃)] moiety bridges the μP–Pt² bond. The [Ag(PPh₃)]⁺ electrophile attacks complex 1 selectively at the Pt²–μP bond to afford, at low T, the cationic cluster [(PHCy₂)Pt¹(μ-PCy₂){κ²P,O-μ-P(O)Cy₂}Pt²{μ-Ag(PPh₃)}(PHCy₂)]⁺(Pt–Pt) (10⁺) in which the [Ag(PPh₃)]⁺ moiety bridges the μP–Pt² bond. Clusters analogous to 10⁺, but without PPh₃ bonded to Ag, are obtained from reactions of 1 with AgOTf, AgBF₄, AgClO₄ and AgCl.