Cation-π and charge-transfer (CT) interactions are pervasive with significant implications in the fields of chemistry, materials science, and biology. However, much less is known about the construction of interfacial assemblies based on the two interactions. Here, by combining cation-π and CT interactions between an acceptor molecule, dicationic naphthalenediimide, and an aromatic donor, pyrene-terminated poly-l-lactic acid, we report the generation of supramolecular complex surfactants (SCSs) in situ at the toluene–water interface. The utilization of SCSs as building blocks enables the fabrication of interfacial assemblies including 2D films, emulsions, and structured liquids. By modification of the redox state of the acceptor molecules under chemical stimulus, the association/assembly and dissociation/disassembly of SCSs can be precisely regulated, imparting intriguing redox-responsive properties to the resulting assemblies.