Tetrapropylammonium and -phosphonium ions, nPr 4 E ؉ , react readily with the polymeric super-Prussian blue derivatives [(Me 3 Sn) 3 M(CN) 6 ] (M ؍ Co, Ir), which are built up of in5nite [ +M+CN+Sn+NC] + chains, a4ording the dimorphic supramolecular assembly [(nPr 4 E)(Me 3 Sn) 2 M(CN) 6 ' 2H 2 O]. All representatives of the latter type are devoid of any extended [ +M+CN+Sn+NC] + backbones. The single-crystal X-ray structures of 1a-P (E ؍ P; M ؍ Co) and 3a (E ؍ N; M ؍ Ir) document new examples of either modi5cation. While Me 4 N ؉ and Et 4 N ؉ ions do not form su7ciently insoluble, R 4 N ؉ -containing assemblies, nBu 4 N ؉ and nPen 4 N ؉ give rise to similar (i.e., R 4 N : Me 3 Sn ؍ 1 : 2) products as nPr 4 N ؉ . The slightly modi5ed super-Prussian blue system [{Me 2 Sn(CH 2 ) 3 SnMe 2 } 1.5 Co(CN) 6 ], 4, reacts with nPr 4 NBr to yield the assembly [(nPr 4 N){Me 2 Sn(CH 2 ) 3 SnMe 2 }Co(CN) 6 ' 2H 2 O], 4a, the powder XRD and solid-state NMR spectra of which strongly resemble those of 3a (with two cis-oriented CNSn(Me 3 )OH 2 ligands). In the absence of suitable single crystals, in particular in the case M ؍ Ir, powder XRD-and multinuclear solid-state NMR results have been carefully examined in view of speci5c similarities with already established structural patterns. The unexpected dimorphism of 1a, which has been described most recently for M ؍ Co, could now also be con5rmed for M ؍ Ir. The experimental results of the present study in total indicate that the superiority of coordinative NPSn bonds over OPSn bonds, in combination with O+H ' ' ' N,C hydrogen bridges, decreases, in the presence of R 4 E ؉ ions, stepwise with the size of R (i.e., from methyl to n-propyl) and of M (i.e., Co vs Ir).