An α-diimine compound (DC) bearing multiple hydroxyl and amine groups presents excellent self-assembly behavior, yielding DC self-assemblies with tunable morphologies ranging from solid spheres, nanotubes and capsules via hydrogen bonds and π-π stacking interactions. These DC self-assemblies provide promising multifunctional hosts for varied metal species. As a typical example, Au nanoparticles are in situ generated and accommodated into both solid and hollow DC self-assemblies by one-pot and two-step fabrication processes, respectively, resulting in the formation of solid and hollow DC/Au hybrid nanostructures. Both solid and hollow DC self-assemblies also enable host Ni(ii) ions to generate DC/Ni(ii) catalysts for the efficient production of porous polyethylene (PE) beads consisting of numerous PE microspheres. Moreover, the yielded PE beads replicate the textural morphologies of the original DC/Ni(ii) catalysts. These DC self-assemblies also might be further utilized to host varied metal species to fabricate versatile DC/metal nanoparticle (Ag, Pt, Pd, etc.) hybrids and porous polyolefin beads with desired morphologies.