A theoretical investigation was carried out using density functional theory at the MN12SX/6-311+G(d,p) level of theory to calculate and compare the photoinduced electron injection for selected members of the anthocyanidin and betalain families. The rate constant of the injection for both families was calculated, and it was verified that the regeneration in the dye during the DSSC operation is caused by an energetic electron injection of the matched electrons in the dye. The present research shows that the rate constant of electron injection of the selected anthocyanidin family was very rapid: Aurantinidin has the overall best injection rate for both families. Aromaticity, the open-circuit voltage \({V}_{{\mathrm{oc}}}\), the \(\Delta {G}_{\mathrm{inject}}\) and \(\Delta {G}_{\mathrm{reg}}\) values for the selected molecule play a vital role in the comparison of both selected families. A prediction of the best dye based on the above properties was made for the maximum efficiency of the DSSC to be achieved.