Four new rod-coil diblock molecules, which had well-defined para-phenylene oligomers (PPP, from biphenyl to quinquephenyl) as rigid segments and poly(ethylene oxide) (PEO, Mw ca. 750) as flexible segments, were synthesized. The chemical structure and the number of repeating unit in PEO coil and PPP rod were characterized by 1H-NMR and MALDITOF mass spectrometry. The diblock oligomers showed good solubility in common organic solvents and aggregated in water as characterized by a blue shift in UV-vis absorption spectra, a red shift in emission spectra, quenching of the fluorescence and formation of the microfibrilla and fractal-like structures. The formation of different supramolecular structures meant that this effort might lead to commercial important highly organized functional materials.