Synthetic macromolecular diblocks sorting into mutivesicular bodies (MVBs) and their fluorophore encapsulation pathways were reported. Renewable resource based diblocks having hydrophobic units and flexible hydrophilic polyethylene glycols (PEG) were custom designed for the above purpose. Single crystal structure was resolved to prove the existence of the strong intermolecular interactions and the formation of unilamellar layer-like self-assemblies. These amphiphilic AB diblocks underwent selective vesicular fission either by outward budding or inward invagination to produce small unilamellar vesicles (SUVs) or MVBs, respectively. Self-rganization parameters such as relative volume (nu(e)) and reduced area difference (Delta a(0)) were determined on the basis of theoretical models, and very good correlation with the experimental results was established for the synthetic-MVBs. Pyrene was encapsulated to study the mechanistic aspects of the MVB formations. An unusual nonlinear trend was observed in the pyrene dynamic excimer formation with respect to the sorting of diblock membrane into MVBs. Strong intermolecular interaction was found to be a critical deciding factor in synthetic diblock membranes to facilitate MVBs. The approach demonstrated here opens up new design strategies for biomimicking of MVBs in synthetic macromolecules which are potential vectors for drug delivery.