The effects of substituents at the bay positions for push pull-type perylenedicarboxylic anhydride dyes on the performance of dye-sensitized solar cells were investigated. The substituents fine-tune the optical and redox properties of the dyes. It turned out that the simplest dye without any substituent results in highest-efficiency cells because of its broadened IPCE spectrum due to intermolecular interactions, which implies that aggregation may not always be detrimental to the performance of the solar cell.