An electrochemically active, rod-coil-rod triblock oligomer, tetraaniline-block-poly(ethyleneglycol)-block-tetraaniline, is studied for its self-assembly in aqueous solutions and in thin films. The oligomer yields different nanoscopic morphological structures according to the solvent used for film preparation: the multi-layered lamella from aqueous vesicular solution and the disordered microdomain structure from the solution in a good solvent. The two samples exhibit distinct electrochemical responses to applied redox potentials. The tetraanilne blocks in the disordered microdomain morphology oxidize from the leucoemeradine base (LEB) to emeraldine base (EB) state at a lower oxidation voltage with a higher current density than those in the lamellar structure. Superior electrochemical activity in the disordered films is attributed to the three-dimensional interconnectivity of the conductive microdomains.