Dendronized poly(methacrylate)-poly(ethylene oxide) (PDMA(58)-b-PEO45) formed as a stoichiometric inclusion complex with a-cyclodextrin. The incorporation of the rodlike PDMA blocks produced no apparent change in the crystal structure, but its steric hindrance on the PEO chain resulted in lower yield as compared with the pure PEO. Moreover, the architectural transition from rod-coil to rod-rod led to a morphological change from spindly aggregates to rods in a binary solvent mixture of N,N-dimethylformamide and water.