Data Accessibility: Accessible on Figshare at , QM-symex provides data in XYZ format, indexed as QM_symex_i.xyz for ease of access,where 'i' represents the order of the structure in the database. In addition to inheriting all properties from QM-sym, QM-symex enriches the data set with information on the first ten singlet and triplet transitions. This includes details such as energy, wavelength, orbital symmetry, transition distance, and other quasi-molecular properties. With the new 38k molecules, the distribution of symmetries within QM-symex is noteworthy. C 2h symmetry occupies a significant proportion of 46%, while C 3h and C 4h symmetries account for 41% and 13%, respectively.