Here, we find that increasing the molecular chain length with repetitive D-A units leads to a gradual increase in the number of intermediate triplet states. As a consequence of the greater number of intermediate triplet states, the RISC-related parameters such as the intersystem crossing rate constant, kISC as well as the kRISC increase with increasing chain length. Most importantly, our approach provides a way to increase the RISC-related parameters while simultaneously preserving the emission wavelength.