As described earlier, solutions of n Bu 4 NCl and K 3 [Cu(CN) 4 ] react with Et 3 SnCl to zeolite-like [(Bu 4 N)(Et 3 Sn) 2 Cu(CN) 4 ] (1), but with Me 3 SnCl exclusively to [(Bu 4 N)(Me 3 Sn)Cu 2 (CN) 4 ] (2), the crystal structure of which is reported here for the first time. The n Bu 4 N + guest ions of 2 are accommodated between planar, negatively charged layers, wherein three-coordinated Cu(I) ions are interlinked by CN and CN.SnMe 3 .NC bridges (2:1). The slightly modified new homologue of 2: [( n Bu 4 N){Me 2 Sn(CH 2 ) 3 SnMe 2 } 0 . 5 Cu 2 (CN) 4 ] (3), displays an almost identical powder X-ray diffractogram as 2 and, moreover, surprisingly similar solid-state NMR spectra for the nuclei 1 3 C, 1 5 N and 1 1 9 Sn. A three-dimensional host framework is postulated to encapsulate the n Bu 4 N + guest of 3, the Sn atoms of adjacent layers being therein tied pair-wise together by trimethylene tethers, (CH 2 ) 3 . For further comparison, the solid-state NMR data of the new coordination polymer [{Me 2 Sn(CH 2 ) 3 SnMe 2 } 0 . 5 Au(CN) 2 ] (5) are also presented.