The corresponding triplet state lifetimes of the AL(DIPY)3 complexes in toluene were in the range of 290-400 ns with the longest triplet lifetimes displayed by 13b and 13h (Error! Reference source not found.). The results are similar to previously reported triplet excited state lifetimes of In(III) and Ga(III) chelates. However, to date only few studies focused on the photoexcitation processes of this class of tris(dipyrrinato) complexes. A comparable trend occurs in ethanolic solutions where the triplet state lifetime underwent a significant decrease (where comparison was possible) of the order of ~90 ns, except for 13e which showed a minor difference. The latter, together with 13h and 13i, displayed the highest triplet state lifetimes in ethanol ~290 ns. Compounds 13c, 13d, 16, and 17 exhibited a triplet state lifetime of around 250 ns with an overall lower value than in toluene solutions. Lastly, we can observe that the respective errors of the fitting curves are smaller in toluene than in ethanol and along with the higher triplet state lifetime values (in toluene) this is indicative that solvent significantly affects the results. Another complementary feature that can be estimated from TA spectra, and the intensity of the ground state bleaching, is the triplet state relative efficiency (Φisc). Since the UV-Vis absorption at the excitation wavelength was set to the same range (0.4-0.5), the relative triplet state yield can be estimated comparing the intensity of the TA spectra of each of the AL(DIPY)3 complexes (preferably by experiments on the same day). The ascending order of the relative triplet state yields in toluene is: 17 < 16 < 13e < 13a, 13f, 13k < 13b, 13c, 20 < 13d < 13i < 13h < 13j; while the order in ethanol is: 13d < 13e, 16, 17 < 13c < 13h < 13i. Therefore, we can postulate that 13h and 13i are more likely for efficient triplet sensitization since they persistently exhibit higher triplet state yields in both solvents; however, 13b and 13k may have the same potential since they display relatively high triplet state lifetimes in toluene whilst they both have moderate fluorescent characteristics. In comparison to toluene, complexes 16 and 17 illustrated a greater triplet absorptivity in ethanol and 13d absorbed less. TA spectra in DCM exhibited intense peaks with longer triplet lifetimes, but as there is degradation we did not proceed with other experiments. The triplet excited state lifetimes obtained were calculated as follows: 13h: 650±40 ns (Fig. ), 13i: 870±38 ns (Fig. ), 13k: 760±34 ns (Fig. ). These differences of the triplet state lifetimes among the solvents support the fact that photoexcitation processes are affected by the nature of the solvent both in the triplet and singlet excited states and imply that non-radiative decay T1 → S0 is also significant.