Multiconfigurational quantum chemistry (MQC) is a computational tool useful to study chemical transformations in which several electronic configurations contribute at the same time. Such situations are usually called strong correlation problems. They are very common in excited-state chemistry, induced either by light (photochemistry) or by a chemical reaction (chemiluminescence). MQC is computationally demanding and as a consequence difficult to apply to large macromolecular systems as those of interest in biology (proteins, nucleic acids, etc.) and also in other fields such as nanotechnology or atmospheric chemistry. In this talk, recent advances developed in the framework of the Quantum Chemistry of the Excited State – Universitat de València (QCEXVAL) group will be presented. They include developments using MQC in macromolecules to determine band lines of absorption and emission spectra of (implemented in MultiSpec and OpenMolcas softwares) and to obtain triplet free energies.