A polyoxometalate-silver ethynide composite cluster, [Ag42(CO3){C≡CC(CH3)3}27(α-A-SiW9Nb3O40)2](-) (1), demonstrates that we can select the binding site of a polyoxometalate to the silver alkynide cluster by tuning the surface charge of the precursor polyoxometalate. Multidimensional and multinuclear NMR spectra revealed that 1 maintains its precise atomic connectivity in the solution.