It is difficult for the same molecule to form vesicular assemblies in water and alipatic hydrocarbon (oil), respectively. Here, we report that chiral oligo(methylene-p-phenyleneethynylene)s bearing hydrophobic or hydrophilic side chains can take extended conformations to self-assemble into vesicle-like particles in a hydrophobic or hydrophilic solvent system. The self-assembly processes are highly independent of molecular design and chemical environments. Based on the analyses of TEM, UV, CD and PXRD data, it is plausible to expect that the vesicular membranes could be stabilized together by π–π stacking interactions between foldamer backbones and collective van der Waals interactions between side chains.