In order to explain the process of quenching of the emission of the S1 state of Pyr2Bpy by TEAO, we also performed the transient absorption study of Pyr2Bpy in the THF:TEOA (5:1) mixtures. As TEOA is an electron donor, we can notably expect the observation of the anion of Pyr2Bpy in case of electron transfer. In fact, the ultrafast photodynamic recorded in THF:TEOA (Figure SI-3.1) is very close to that observed in pure THF (Figure ), and only the spectral signature of the S1 state of Pyr2Bpy is identified in the transient spectra. These data are showing that the quenching of the S1 of by TEOA does not lead to the stabilization of a reduced separated ion pair (SIP). Furthermore, we can rule out the hypothesis that the TEOA favor the direct internal conversion S1 → S0 because we observed in THF and THF:TEOA the same emission spectra and stimulated emission band resulting from the -delocalization of the LUMO (MICT state). Thus, the quenching of the S1 state of Pyr2Bpy by TEOA is more likely a reductive quenching followed by the ultrafast recombination of the geminate pair [TEOA + , Pyr2Bpy -]. The low polarity and the viscosity of the THF:TEOA mixture might facilitate the intrapair geminate recombination (Scheme 2). Similar results have been reported for the photoreduction of the n* S1 state of the 4,4'-bipyridine for which intrapair recombination was found to be the main deactivation path (deact = 95 %) even in highly polar dielectric solvent (MeCN, MeCN-H2O mixture) . In many photocatalytic applications, TEOA is introduced as a sacrificial electron donor. Our result show that at high concentration it can interact directly with some excited state of the photosensitized ligand, and thus contributes to the reduction of the overall photocatalytic yield by quenching the excited state because the deactivated excited state will not contribute anymore to the activation of the catalytic site. This point can be particularly important in the context of our PyrBpy porous polymer for which the Pyrene-Bipyridyl moieties constitute the backbone of the porous artificial antenna in which TEOA are adsorbed. Under these conditions, the excited state interaction and quenching can strongly compete with the photoactivation of the catalytic site.