We fabricated electrostatic self-assembled thin films with poly(thiophene-3-acetic acid) (PTAA) as a polyanion and a positively-charged second-order NLO chromophore as a cation. UV-Vis, FT-IR, and second-harmonic generation (SHG) were measured in order to investigate the process of anion and carion adsorption and to understand the relationship between structure and optical properties of the ultra thin films. UV-Vis and FT-IR spectra of these films indicated that PTAA and the NLO chromophore formed a layer-by-layer structure. SHG measurements suggested that the NLO chromophores were non-centrosymmetrically aligned within the self-assembled films.