An alkylsulfonated polyaniline, poly(aniline-N-butylsulfonate)s (PANBS), was assembled by the layer-by-layer (LBL) assembling technique as an electroactive anionic polymers for the layering. The counter ions for PANBS layer were polyaniline (H+ doped) and vinylbenzyldimethyl-n-alkylammonium salts (VBAA) as the conductive and insulating polycation, respectively. High color contrast was observed when the electrochromic (EC) film was composed alternatively of the PANBS/PAN and PANBS/VBAA layer. Interlayer insulating gap controlled by the alkyl chain length of VBAA, was an important factor to increase EC response of the window assembled by the LBL method.