Six organic sensitizers containing 3,4-ethylenedioxythiophene and thienothiophene in the bridged group are designed and synthesized, which under standard global AM 1.5 solar conditions, the device using JK-184 gave a conversion efficiency of 8.70%. The photovoltaic performance data are quite sensitive to the structural modification of sensitizer. The hexyl substituent of the hexyloxy group on the sensitizer was shown to improve the efficiency and stability. The device based on the JK-184 with an ionic liguid electolyte exhibits an excellent stability after 1000 h of light soaking at 60 degrees C.