To investigate the effect further, quantum yields were calculated for the D2-4 molecules along with the trans-PyChal monomer in free solution (Figure ), with D2-4 displaying a relatively wavelength-independent quantum yield, while the trans-PyChal monomer shows a wavelength-dependent quantum yield. Despite a reduction in quantum yield for D2-4 due to oxygen quenching, there is still a clear increase over the quantum yield for the trans-PyChal monomer. Thus, the trans-PyChal monomers are inhibited from achieving their true potential quantum yield at shorter excitations, with the longer excitation wavelengths approaching these values. Our data strongly supports the concept of a difference in wavelength-dependent excited-state lifetimes being responsible for the increased reactivity at longer wavelengths for bimolecular reactions.