Three‐Component Self‐Assembly Changes its Course: A Leap from Simple Polymers to 3D Networks of Spherical Host–Guest Assemblies

One‐pot self‐assembly reactions of the polyphosphorus complex [Cp*Fe(η(5)‐P(5))] (A), a coinage metal salt AgSbF(6), and flexible aliphatic dinitriles NC(CH(2))(x)CN (x=1–10) yield 1D, 2D, and 3D coordination polymers. The seven‐membered backbone of the dinitrile was experimentally found as the borderline for the self‐assembly system furnishing products of different kinds. At x<7, various rather simple polymers are exclusively formed possessing either 0D or 1D Ag/A structural motifs connected by dinitrile spacers, while at x≥7, the self‐assembly switches to unprecedented extraordinary 3D networks of nano‐sized host–guest assemblies (SbF(6))@[(A)(9)Ag(11)](11+) (x=7) or (A)@[(A)(12)Ag(12)](12+) (x=8–10) linked by dinitriles. The polycationic nodes represent the first superspheres based on A and silver and are host–guest able. All products are characterized by NMR spectroscopy, mass spectrometry, and single‐crystal X‐ray diffraction. The assemblies [(A)(12)Ag(12)](12+) were visualized by transmission electron microscopy.