This introductory chapter starts with describing the principle of self-organization: the ability of a system to spontaneously arrange its components in a purposeful (non-random) manner, driven by the interaction between these components. The use of non-covalent interactions is highlighted for making temporal, tuneable, self-organized structures. As the focus in this thesis will be on self-organization of polyelectrolytes in the presence of oppositely charged species like surfactants and/or dyes, the physical chemical properties of these building blocks are described. In this sense polyelectrolytes are charged macromolecules whose manifold charged groups, combined with their polymeric properties, makes polyelectrolytes ideal guides or templates for self-organization based on electrostatic interactions. Charged surfactants are amphiphilic molecules, characterized by the presence of an electrostatic charge and an apolar (tail) section, which exhibit concentration-dependent self-organization due to the effective interaction between their apolar moieties. Dyes are molecules that absorb light at specific (visible) wavelength ranges and which may also self-organize depending on concentration due to the presence of large conjugated systems which engage in π-π interactions. In this thesis self-organization is aimed at being the result of the mutual action of both electrostatic and one other type of interaction. For polyelectrolyte-surfactant complexes the establishment of organized 3D structures is described, whereas for polyelectrolyte-dye complexes emphasis is also given to the phenomenon of metachromasy, a shift in the visible light spectrum of the dye in its complexed state onto a polyelectrolyte template. This introductory chapter ends with the aim and outline of this thesis as outlook.