We have successfully prepared a new class of self-assembled biomaterial: a polypeptideblock-polypseudorotaxane diblock copolymer. This diblock copolymer is comprised of an R-helical polypeptide rod, based on γ-benzyl-L-glutamate, and an originally coiled segment P(EO19-r-PO3); it forms inclusion complexes with R-cyclodextrins (R-CDs) to give crystalline polypseudorotaxanes. Formation of the polypseudorotaxane converts the conformation of P(EO19-r-PO3) from a flexible chain into a rodlike structure, which results in a novel block copolymer exhibiting a rod-rod conformation. Intrinsic interactions (e.g., the polypseudorotaxane's channel-type crystallization, the polypeptide's secondary structure, and microphase separation) within and between these rod-rod diblock copolymers contribute to their hierarchical self-assembly behavior, which we characterized using DSC, 1 H NMR spectroscopy, 13 C CP/MAS NMR spectroscopy, WAXS, and SAXS. The data obtained from the WAXS and SAXS studies clearly indicate the formation of juxtaposed bilayer-like nanostructure featuring hexagonally packed PBLG stacks and channel-type polypseudorotaxane moieties.