This report reviews the recent advances in morphological studies on block copolymer and related multiple component polymer systems that possess characteristic chain connectivity and non-covalent bonding interactions, which were mostly done in our research group. Among many topics, three types of multi-phase systems are picked up and examined in this article. The first system consists of multiblock terpolymers. Hierarchical structures having double periodicity have been formulated for sample polymers including block chains with different lengths. The second one is represented by star-shaped terpolymers of the ABC type, which easily form three-phase cylinder-like structure whose cross sections exhibit periodic tiling structures. They show several Archimedean tilings and one of them forms quasicrystalline tiling with dodecagonal symmetry. The third one is composed of block copolymer/block copolymer blends or a block copolymer/homopolymer blend with hydrogen bonding interactions. It has been found these blends represent very striking phase structures including new mesoscopic tiling structures. These structures with new self-assembly manners due to strategic molecular design open the door to production of many highly functional materials.KEY WORDS: Block Polymer / Morphology / Hierarchical Structure / Archimedean Tiling / Quasicrystalline Tiling / Studies on self-assembling structures of block copolymers have started in the 1960s, when the first reports on the discovery of highly periodic structures for block copolymers in bulk and in concentrated solutions were published.1,2 Successively, these structures were verified by measurements of viscoelastic and thermal properties 3,4 and finally observed by morphological studies with electron microscopy. 5,6 The basic concept of morphological transition with composition was proposed during this period, 7 since then the concept has been the basis of any morphological studies in block copolymerbased complex systems. Subsequently, started from the 1970s through the early 1990s, morphological features were extensively studied both by theoretical 8-10 and experimental works.11-13 During this period, physical aspects of several properties such as phase transition and phase stability were fully focused, where the order-order phase transition 9,14 or order-disorder transition 9,15 was investigated by varying the magnitudes of the external field such as shear flow and/or temperature. Moreover, nanophase-separated structures were explored at the molecular level using neutron scattering methods by introducing deuterium labeling technique in this period. 16,17 The next generation occurred during the late 1980s and 1990s when complex morphologies with periodic surfaces were identified, some of which included bicontinuous structures for two-component linear 18 and star-branched 19 copolymers, as well as tricontinuous structures for three-component linear terpolymers. 20 The peculiar morphology for an amphiphilic diblock copolymer-aluminosilicate nanocomposite was also reported. 21 Among...