The long-range ordered tetragonal single-crystal structures formed by loading optimal amounts of hydrophobic Au nanoparticles (NP) and hydrophilic NPs into the respective blocks of a PS-b-P4VP was investigated. A lamellar PS-b-P4VP diblock copolymer was used in all of the experiments. Hydrophilic pyridine-coated CdSe NPs having a core size of 3.5 nm were synthesized using a modified procedure. A periodic structure for the P4VP/CdSe domains along the in-plane direction of the pristine P4VP lamellae. The Pb-b-P4VP/CdSe composite and Au NPs were mixed in THF. The diblock copolymers formed body-centered cubic, face-centered cubic, and simple cubic ordered spherical morphologies. It was observed that presynthesized hydrophilic CdSe NPs and hydrophobic Au NPs can collectively self-organize in the two distinct blocks of a PS-b-P4VP diblock copolymer to form a highly ordered structure.