Four (D-pi-A)(3)L-2 phenothiazine dyes (PTZTB14) and a reported reference dye (R-SB) with a mono D-pi-A chain were utilized as photosensitizers for dye-sensitized solar cells. In the skeleton of the dyes PTZTB14, three D-pi-A chains (D-pi-A)3 were connected by flexible linker of n-hexyl or n-dodecyl group (L-2) to build the (D-pi-A)(3)L-2 configuration. The effect of both the auxiliary donors and linkers with different length of carbon chains upon the photophysical, electrochemical as well as photovoltaic properties of the (D-pi-A)(3)L-2 dyes were further investigated. Results reveal that the dyes PTZTB34 containing the auxiliary donor of 4-octyloxyphenyl group show a higher molar extinction coefficient, a broader IPCE response region, and a higher HOMO value than those of PTZTB1-2 and R-SB. Among all of the devices, the cells based on PTZTB2 and PTZTB4 exhibit a higher open circuit voltage due to that the charge recombination is blocked significantly by the n-dodecyl linkers. Meanwhile, a maximal power conversion efficiency of 6.66% is achieved by the device fabricated with PTZTB3. Besides, it is noteworthy that the (D-pi-A)(3)L-2 dyes possess a superior adsorbed stability on TiO2 interface than that of the reference dye as a result of the three anchors in a molecule of the former. (C) 2018 Elsevier Ltd. All rights reserved.