Featured on the cover of the Macromolecules, Prof. Guan and graduate student Guobin Sun demonstrate an efficient catalytic synthesis for preparation of soluble molecular nanoparticles with extremely high molecular weight (Mn~ 60 million g/mol) and narrow polydispersity (PDI < 1.20). The simplicity and efficiency of this method make it promising for various nanoparticle-based applications including catalyst support and multivalent ligand presentation.