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Using a combination of various techniques, viz., turbidimetry, dynamic/static light scattering, analytical ultracentrifugation, small-angle neutron scattering, fluorescence spectroscopy (with the use of pyrene as a probe), cryogenic transmission electron microscopy, we found that, if the certain conditions are met, the interpolyelectrolyte complexation of the star-shaped polyions and star-like micelles of ionic amphiphilic diblock copolymers with the oppositely charged linear polyelectrolytes (PEs) or double hydrophilic diblock copolymers can result in the formation of soluble in aqueous media distinctly compartmentalized nanosized complex species. The obtained experimental results strongly suggest that the formed macromolecular co-assemblies have peculiar "core-corona" (star-shaped PEs) or "core-shell-corona" (star-like micelles of ionic amphiphilic diblock copolymers) structure. A hydrophobic core (star-shaped polyelectrolytes) or a hydrophobic shell (star-like micelles of ionic amphiphilic diblock copolymers) of each of the complex species represents an essentially water-insoluble interpolyelectrolyte complex (IPEC) incorporating the oppositely charged polyelectrolyte components in 1 : 1 charge ratio. In the case (a) of star-like polyionic species interacting with the oppositely charged linear homopolyelectrolyte, a hydrophilic corona is composed of free (excessive) PE branches that are not coupled with the fragments of the oppositely charged linear polyions. In the case (b) of star-like polyionic species interacting with the oppositely charged double hydrophilic diblock copolymers, a hydrophilic corona can be built up only from nonionic hydrophilic blocks of double hydrophilic diblock copolymer (at 1 : 1 charge stoichiometry) or apparently can be mixed and formed by those nonionic hydrophilic blocks and free (excessive) PE branches that do not form interpolymer salt bonds (at charge stoichiometries considerably deviating from 1 : 1). The main feature of the macromolecular co-assemblies resulting from the interaction of the star-like polyionic species (star-shaped PEs or micelles of ionic amphiphilic diblock copolymers) with the oppositely charged linear homopolyelectrolytes or double hydrophilic diblock copolymers is their pronounced compartmentalized structure. We believe that such novel complex macromolecular architectures of micellar type are very promising and will be in demand for their future applications in rapidly developing nanotechnologies, for expample, as nanocontainers and nanoreactors.