Self-assembly of [Ag(CN)2]-, 3-cyanopyridine, and iron(II) gives triple interpenetration of three-dimensional spin crossover (SCO) networks with the NbO topology, which interact each other via argentophilic interactions. Superposition of the networks along the c-axis defines an infinite mosaic of trigonal and hexagonal cross-sectional tubes where water molecules are installed. The structural changes associated with the SCO tune the homoatomic interactions and induce an uncommon change of the lattice volume.