IRG4 seeks to understand and control the organization of particle mixtures to generate photonic and electronic architectures in which non-additive functions are imparted by the collective properties of the array. Co-assemblies will incorporate multiple, distinct particle populations that vary in composition and consequently in their response to various directed self-assembly approaches (Figure, top/middle). Learning how to achieve desired assembly outcomes despite these differences, and to find ways to take advantage of them for increased control, will set the stage for a new era of nanomaterial-enabled device applications well beyond those proposed here. Three general classes of multicomponent assemblies will be investigated, incorporating new types of functional particles and spanning a wide range of organizational ordering schemes (Figure, bottom): (1) well-ordered arrays with single-particle positioning relative to underlying electrical contacts for fundamental studies of bioinspired synchronization in electronic oscillator networks; (2) arrays with intermediate order that will collectively define the spatial refractive index profile to manipulate light in new ways; (3) disordered assemblies of scattering particles to advance understanding of ‘random’ photonics, with a focus on lasing and nonlinear wave mixing.