We evaluated the performance of several methods for predicting excited states in IPA and TPA across vacuum, solution, and crystal environments. First, we optimised the ground states using the DFT method with B3LYP, PBE0, and ωB97XD functionals, and then computed the vertical excitations of the first five singlet and triplet states with the timedependent DFT (TD-DFT) method at the corresponding ground state minima. We also explored the resolution of identity coupled cluster method to the second order (RI-CC2) and the multi-state complete active space second-order perturbation theory ((MS-)CASPT2/CASSCF (14,11)) with the aug-cc-pVDZ basis set for describing the lowestlying singlet and triplet states. For the RI-CC2 calculations, the ground state geometries were optimised at the CC2 level of theory, while for the CASPT2 computations, the ωB97XD/augcc-pVDZ ground state geometries were used. Solvent effects were considered by applying the polarisable continuum model (PCM) in the (TD-)DFT and CASPT2/CASSCF calculations, while the conductor-like screening model (COSMO) was used in the RI-CC2 computations.