In addition, we have determined the emission yield for exc = 380 nm, to be em = 0.78 (see SI). The transient emission spectra of Pyr2Bpy have been characterized by TCSPC measurements (Figure ). We observe a unique emission band that is decreasing without spectral change and with a shape and maximum that correspond to the steady state emission spectrum. The decay trace at the maximum (440 nm) is well fitted using a mono-exponential decay function, with THF= 1.4 ns. The spectra and the value that we obtained for Pyr2Bpy in THF are in good agreement with the data reported for toluene (em = 0.88, τ = 1.4 ns), dichloromethane (em = 0.62, τ = 1.7 ns) and acetonitrile (em = 0.42, τ = 2.4 ns). This emission band is unambiguously assigned to the lowest singlet excited state (S1) of Pyr2Bpy. Based on the literature data, the nature of this excited state is not changed by the polarity of the solvent.