Block copolymers, which can be composed of molecules with tunable chemical and physical properties, are attractive materials for many engineering applications due to their diverse and controllable nanoscale morphologies. Our group’s effort in this area is focused on developing block copolymers which interact with functional materials to form composite nanostructures. Examples include small molecule dyes, proteins, and magnetic nanoparticles; all of which have geometry-dependent properties which are enhanced by alignment and ordering. Additionally, we study the fundamental science of how blending these additives with block copolymers affects the resultant morphologies of both materials. Here, we are concerned with understanding questions such as: which factors control solubility of a material of interest in the blocks of the polymer; what determines its organization within a specific domain and how can this be tuned; under what conditions does the polymer structure drive the additive structure and vice versa; how do ionic interactions impact self-assembly; and how is the segregation between blocks affected by the presence of additional materials? Technological and scientific development in this area will contribute to understanding the design rules for creating ordered and functional materials using block copolymer templates, with applications in photonic and magnetic materials among other fields.