Multiphase polyolefin particles consisting of polyethylenes with different microstructures were synthesized using [kappa(2)-(N,O)Ni(II)-Me(L)] catalyst precursors via a two-step dispersion-based approach. First, crystalline seed particles were directly generated by aqueous polymerization of ethylene using a water-soluble catalyst precursor or via miniemulsion polymerization. The second softer dispersed phase, consisting of a low crystalline highly branched low molecular weight polyethylene or ethylene-norbornene copolymer, was generated in the presence of this seed via aqueous polymerization using a second water-soluble catalyst precursor or via miniemulsion polymerization. Particles with different nanoscale morphologies, namely core-shell, "dumbbell" or "sea urchin"-like, were formed as observed by TEM and AFM. The obtained nanocomposite dispersions formed continuous semicrystalline films.