Self-assembly of nanoscopic components into higher-order architectures defines the forefront of fundamental nanoscience research and is important for the development of new materials with potential applications in optoelectronics, high-density data storage, catalysis, and biological sensing. In my talk, I will discuss how the peculiar nature of electrostatic and photoinduced dipole-dipole forces acting between nanoscale components can mediate their self-assembly into various superstructures and materials. I will show how the interactions underlying self-assembly can be studied and understood in quantitative detail, and how they can be tailored to synthesize unusual higher-order architectures: ionic-like crystals of nanoparticles, crystalline aggregates that can be assembled and disassembled by light, as well as extremely durable and yet very flexible metallic structures. Since these materials display a range of novel optical, electrical and mechanical properties, the discussion of experimental results will be accompanied by theoretical analyses combining elements of thermodynamics, statistical mechanics, electrodynamics and elasticity.