Chemical polymerization of 3,4-ethylenedioxythiopherie (EDOT) in the presence of single-chain schizophyllan (s-SPG) gave water-soluble nanocomposites with the very uniform globular structure. The findings indicate that s-SPG is capable of acting not only as a one-dimensional host to create fibrous architectures but also as a neutral host to create nanoparticles. The mechanism is reasonably explained by the difference in the hydrophobicity of guest polymers or assemblies.