The fluid films withdrawn from nano-suspensions of particles, polymer solutions, and surfactant micelles are assuming ever-increasing importance in emerging technologies that develop 2D materials with attractive electrical, magnetic or optical properties. The nano-fluid confined between the film surfaces tends to self-assemble into 2D layers and a 2D in-layer structure. The particle structuring depends on the particle concentration, position of the layer, and film thickness. The particle structure formation inside the film versus film thickness, particle concentration, and polydispersity have been experimentally and theoretically studied. The film-confinement ability to self-assemble the nano-matter in a 2D structure has been explored to develop photonic crystals.