We have developed a new chemical route for ZnO nanostructures preparation that combines anodization and thermal annealing in a very convenient technique to obtain crystalline nanostructures on stiff and flexible (Kapton HN®) substrates. The preparation parameters like the type and the concentration of electrolyte, the anodization voltage and the current were tailored to obtain the nanosized ZnO structure. The relation between size and morphology of the nanostructures and the preparation parameters were investigated by means of scanning electron microscopy (SEM), atomic force microscopy (AFM), Glancing Incidence X-Ray Diffraction (GIXRD) and photoluminescence (PL). The structures are composed of nanoparticles forming elongated aggregates with chain-like morphology. The diameter of the particles is ranging from 10 to 75 nm and the length of then chains is more than 1 μm. ZnO crystalline phase was confirmed by structural analysis with GIXRD for samples annealed at 350 and 400 °C.