Polymeric metal-organic nanocapsule networks (polyMONCs), where metal-organic nanocapsules (MONCs) are connected by functional polymers, could possess the properties of traditional polymers and also retain the structures of MONCs. In this work, we constructed novel polyMONCs based on Mg-seamed pyrogallol[4]arene-containing MONCs through supramolecular coordination-driven self-assembly. The MONCs can be successfully polymerized using poly(ethylene glycol) as the linker, and the prepared polyMONCs can be further made into gels with self-healing properties and stimuli responsiveness. Advantageously, single crystals of MONCs cross-linked by ethylene glycol/diethylene glycol were obtained, giving us direct perspectives to mimic and investigate the self-assembly process of polyMONCs.