Three　novel　phenothiazine　dyes　(JY31-33)　featured　oligothiophene　π-bridge　have　been　designed,　synthesized　and　applied　as　photosensitizers　for　highly　efficient　dye-sensitized　solar　cells　(DSSCs).　The　introduction　of　alkyl　chains　on　oligothiophene　π-bridge　is　found　to　significantly　improve　the　open-circuit　voltage　of　the　resultant　device.　Phenothiazine　bearing　a　4-butoxyphenyl　group　as　the　secondary　donor　exhibits　a　stronger　electron-donating　ability　and　a　positive　acceleration　on　the　short-circuit　current　density　and　open-circuit　voltage.　The　dye　JY33　containing　a　secondary　donor　and　two　alkyl　chains　finally　gives　a　high　efficiency　of　7.48%　under　the　100　mW　cm-2　simulated　AM1.5　sunlight,　with　a　short-circuit　photocurrent　density　(Jsc)　of　17.18　mA　cm-2,　an　open-circuit　photovoltage　(Voc)　of　742　mV　and　a　fill　factor　(FF)　of　0.59.　©　2016　Elsevier　B.V.　All　rights　reserved.