The photophysical and photochemical processes of the experimental dyes ZS11 and ZS12 containing phenyl-cyanoacrylic acid (PCA) and ethynyl-PCA (EPCA) group were studied by DFT and TD-DFT systems to develop their applications in solar cells. First, their geometry, absorption spectra, chemical reaction parameters, electron transfer and dye activity were systematically studied. The photoelectric conversion efficiency (PCE) was predicted, and it was found that the PCE of ZS12 (9.974 %) was higher than ZS11 (7.171 %), which was consistent with the experimental trend (the PCE of ZS12 is 10.4 ± 0.3 % and the PCE of ZS11 is 9.0 ± 0.3 %). Secondly, the dye was co-sensitized with the chlorophyll derivative CHL-1c, and the co-sensitization system’s interaction force, excited state characteristics, electron transfer mechanism and electron transfer rates were studied. The results show that the JSC of all co-sensitive systems (the JSC of ZS12-CHL is 22.363 mA/cm2 and the JSC of ZS11-CHL is 23.978 mA/cm2) is significantly higher than that of monomers (the JSC of ZS12 is 16.112 mA/cm2 and the JSC of ZS11 is 11.051 mA/cm2). It can be inferred that the optoelectronic performance of co-sensitizing systems is better than that of monomers. This study demonstrates that the use of dye molecules co-sensitized with chlorophyll derivatives can enhance DSSC performance from multiple perspectives, providing insights for further improvements.