Dithienosilole (DTS) and dithienogermole (DTG) are useful building units of pi -conjugated organic materials. In the present work, donor-pi -acceptor (D-pi -A) dyes with bis(dihexyloxyphenyl)aminophenyl, DTS or DTG, and pyridine or cyanoacrylic acid as the donor (D), the pi -conjugated linker (pi), and the acceptor (A) units, respectively, were prepared and their optical properties were investigated. The D-pi -A dyes exhibited strong absorption in the visible region, indicating efficient intramolecular donor-acceptor interaction. The addition of trifluoroacetic acid to solutions of pyridine-containing dyes led to red-shifts of the absorption bands as a result of pyridinium salt formation. Similar red-shifts were observed for cyanoacrylic acid dyes, which were due to the enhanced formation of neutral dyes relative to the separated ion pairs. The D-pi -A dyes, however, showed similar absorption spectra when attached to the TiO2 surface, indicating that the dye-TiO2 electronic interaction was rather weak. In contrast to the finding that these dyes exhibited similar optical properties regardless of the pi -linker (i.e., DTS or DTG), dye-sensitized solar cells (DSSCs) based on DTG-containing dyes exhibited superior performance compared to those based on DTS-containing dyes. Electrochemical impedance spectroscopy measurements supported the higher performance of the DSSCs with DTG-containing dyes.