New organic dyes (D1, D2, and D3) containing a phenanthrothiadiazole unit as a π-conjugated system, a triarylamine as an electron donor, and a cyanoacrylic acid moiety as an electron acceptor were synthesized. The optical and electrochemical properties of dyes D1, D2, and D3 were investigated, and their performance as sensitizers in solar cells was evaluated. Dye-sensitized solar cells based on dye D3 produced a photon-to-current conversion efficiency of 5.23% (Jsc = 9.70 mA/cm2, Voc = 0.77 V, ff 0.70) under 100 mW/cm2 simulated AM 1.5 G solar irradiation.