We synthesized and structurally characterized the first cyanoaurate-based organotin polymer Me(3)Sn[Au(CN)(2)] (1), which exhibits unusual ion-exchange properties. In the structure of 1, the void space of the 2D grids formed via Au...Au bonding is filled by arrays of zigzag chains joined by weak Au...Au interactions. Interestingly, the practically insoluble polymer 1 shows unusual ion-exchange properties. The polymer Me(2)Sn[Au(CN)(2)](2) (2) was obtained in the metathesis reaction of 1 with Me(2)SnCl(2). Compound 2 displays cyanide-bridged uninodal four-connected 3D nets with 6(5).8 topology corresponding to the CdSO(4) prototype. Interestingly, 2 can be converted back into 1 by metathesis with Me(3)SnCl. Moreover, we performed a series of metal-exchange experiments in which 1 was soaked in aqueous solutions of bivalent transition-metal cations M(2+) (M = Co, Ni, Cu, Zn). As a result, 1 was completely converted into transition-metal cyanoaurates. To our knowledge, this represents the first study revealing the metal-exchange properties of a cyanoaurate-based heterometallic polymer.