Reactions of the polynuclear palladium carboxylate complexes (binary palladium carboxylates and palladium nitrosyl carboxylates) with acetonitrile in some common organic solvents are described. It was found that reaction of palladium acetate Pd₃(μ-CH₃CO₂)₆ with acetonitrile and benzene leads to the formation of a binuclear complex Pd₂(C₆H₄-o-C(NH)CH₃)₂(CH₃CO₂)₂ containing molecules of orthometallated 1-phenylethanimine formed as a result of C–C-coupling of acetonitrile and benzene. Nitrosyl carboxylate complexes Pd₄(NO)₂(RCO₂)₆ promote more complicated transformations of acetonitrile that leads to the formation of coordinated acetimidic anhydride, which was found in Pd₅(CH₃C(N)OC(N)CH₃)(NO)(NO₂)_x(RCO₂)_7−x clusters. Structures of all the complexes contained products of acetonitrile transformations and a new palladium nitrosyl carboxylate Pd₄(NO)₂(cyclo-C₆H₁₁CO₂)₆ was studied with XRD. Analysis of the structures allowed finding a “building block” of palladium nitrosyl carboxylate clusters, that is a 4-nuclear metal chain –Pd(μ-RCO₂)₂Pd(μ-NO)(μ-RCO₂)Pd(μ-RCO₂)₂Pd–.