Following an earlier work, 26 0-0 transition energies of methylpyrimidine (MP) derivatives were computed using an SA2-CAS(10e,8o) active space consisting of three π, three π * , and two n N orbitals. Geometry optimizations and vibrational frequency calculations were performed with the cc-pVTZ basis set, whereas single-point energies were obtained with the aug-cc-pVTZ basis set.