Thienyl groups were incorporated into three porphyrin dyes, ZZX-N7, ZZX-N8 and ZZX-N9, with D-∏-A configuration to broaden the absorption spectra for dye-sensitized solar cells (DSCs). With the increase of π-conjugation from ZZX-N7, ZZX-N8 to ZZX-N9, a systematic red-shift of absorption was observed. However, the broadened spectra were not correlated proportionally to their photovoltaic performance. It was found the power conversion efficiency increased in the order of ZZX-N7 < ZZX-N8 < ZZX-N9 under low dye-loading condition; whereas it decreased in the order of ZZX-N7 > ZZX-N8 > ZZX-N9 under high dye-loading condition. Further study showed that the increased EtOH/THF volume ratio in dye solution not only increased dye-loading density but also promoted dye aggregation. A trade-off between the blocking effect of the adsorbed dyes and the dye aggregation under different dye-loading densities was observed. Under optimized conditions, ZZX-N8 sensitized cell exhibited energy conversion efficiency of 7.78% under AM1.5G condition.