Bacteriochlorophyll(=BChl)s‐c/d/eare known to be major pigments constructing the main light‐harvesting antennae of photosynthetic green bacteria. In this study, methyl bacteriopheophorbide‐dderivatives having a series of alkyl or alkenyl substituents at the 8‐position and their zinc complexes were synthesized, and their visible absorption spectra and self‐aggregation in a solution were examined. It was shown that the C8‐substituents conjugating with the chlorin &pgr;‐system cause red‐shifts of the Qxpeaks in their monomeric forms, but do not strongly affect the supramolecular structure of the self‐aggregates along the Qyaxis. Furthermore, 31‐epimerically pure Zn‐MBPhe‐fanalogues possessing the C8‐formyl group were also synthesized, and their spectral characteristics were compared to those of the C7‐formyl compounds. It was found that the C8‐formyl group cause drastic spectral changes both in monomeric and oligomeric forms compared to the spectra of Zn‐MBPhe‐fhaving the C7‐formyl group. For example, self‐aggregates of the former showed more red‐shifted Qypeak in 6&percent;THF‐H2O than the latter, and larger diastereomeric control in the oligomeric Qypeaks was observed for C8‐formyl derivatives than for C7‐formyl compounds. © 2004 American Institute of Physics