Nanophase-separated poly(2-hydroxyethyl methacrylate)-l-polyisobutylene (PHEMA-l-PIB) amphiphilic conetworks were obtained by crosslinking alpha,omega -bismethacrylate-terminated polyisobutylene (PIB) via copolymerization with silylated 2-hydroxyethyl methacylate, followed by the hydrolysis of the silylether groups. Morphology development of a sample containing 64% PIE was monitored by means of transmission electron microscopy (TEM), atomic force microscopy (AFM), and small-angle X-ray scattering. For comparison, the morphology of a sample containing 53% PIE was investigated by AFM. The dry conetworks exhibited hydrophilic and hydrophobic phases with average 8-10-nm domain sizes and were swellable in water as well as in heptane. Swelling amphiphilic conetworks with aqueous cadmium-chloride solution followed by exposure to H,S resulted in nanosized CdS clusters located in the amphiphilic conetworks, that is, for the first time, new inorganic organic hybrid materials composed of CdS semiconducting nanocrystals and PHEMA-l-PIB amphiphilic conetworks were prepared.