Self-assembly is an important route to organized soft matter, e.g. for nanoelectronics, solar cells or drug carriers. We have developed a concept of electrostatic self-assembly for the formation of supramolecular nano-assemblies in solution. Macroions become interconnected by oppositely charged stiff organic ions, yileding assemblies of various shapes. We have revealed a relationship of the size of the self-assembled nanoparticles with the free energy of the association. The exchange of entropy encodes the nanoparticle shape and anisotropy. Focus of this project now are thermodynamics and nanoscale structure at different temperatures. This will give insight into the self-assembly process from a fundamental point of view and might open new ways for nanoparticle structure tailoring. The model system will consist of a cationic poly(amidoamine) generation four and eight dendrimer and a set of oppositely charged azo dyes. This choice permits the modification of interaction strength, flexibility of the particles, geometric constraints and charge compensation providing a substantially deeper understanding of the assembly process. For this, the nanostructures will be investigated by SANS.