One of the main problems encountered in the dye-photosensitization of wide band semiconductors which have potential use for low-cost hybrid solar cells is the non-specific aggregation of the dye molecules. This effect leads to strong quenching of the dye fluorescence and thus to low device efficiencies. We have designed and synthesized novel chromophores which self-assemble by specific supramolecular interactions forming nanostructures which are strongly fluorescent. Our fully synthetic molecules are mimics of the natural self-assembling bacteriochlorophylls c, d and e that form the light-harvesting apparatus of green photosynthetic bacteria. Our biomimetic approach has allowed us to prepare, in fairly large amounts, various self-assembling porphyrins and chlorins with tailored properties. We can control both the chirality and the optical properties through ordering the transition dipole moments of the chromophores within the self-assembled nanostructure. Very broad absorption spectra, beneficial for efficient light collection over almost the entire visible spectrum, characterize some of our assemblies. Upon anchoring the self-assembled chromophores onto nanocrystalline titania with different grain sizes the fluorescence is not quenched. This fact encourages us to fabricate hybrid devices and measure their photocurrent generation efficiencies. (C) 2003 Elsevier B.V. All rights reserved.