For OLU -solvated in water (Fig. ), schemes (i)-(iii) produce visually similar results, although marginal improvement in the accuracy relative to full-system TDA results is obtained as the active space increases, as indicated by the reduced RMSD values. In contrast, significant improved agreement with the full-system TDA results is obtained by adding the solvent→chromophore chargetransfer excitations to the active space (scheme (iv)), reducing the RMSD from 0.258 to 0.032 eV. Based on our argument above, these results highlight the significance of capturing the entanglement between the occupied orbitals on the chromophore and solvent molecules for the accurate modeling of the S 1 excited state of the solvated OLU -. Interestingly, the "fully entangled" ALMO-TDA+CT model (scheme (v)) systematically overshoots the full-system TDA results, yielding lower excitation energies with a mean-signed error of -0.064 eV and a larger RMSD of 0.065 eV than that given by scheme (iv). While not entirely expected, this is possible since ALMO-TDA and full-system TDA are two linearresponse excited-state methods that use different reference orbitals. There is no variational principle to ensure that the excitation energies provided by full-system TDA must be lower than those obtained from ALMO-TDA.