The reliability of density functional theory and other electronic structure methods isexamined for anharmonicities and spectroscopic constants of low-lying valence electronicexcited states. The equilibrium bond length re, harmonic vibrational frequency ωe, rotationalconstant Be, centrifugal distortion constant e D , and vibration-rotation interaction constant αe,have been determined for low-lying singlet excited states of BF, CO, N2, CH+, and NO+.Predictions using configuration interaction singles, equation-of-motion coupled-cluster singlesand doubles, and various time-dependent density functional methods have been made using the6-31G*, aug-cc-pVDZ, and aug-cc-pVTZ basis sets and compared to experimental values. Timedependentdensity functional theory compares favorably to equation-of-motion coupled-clustertheory for the properties considered, but errors are substantially larger for excited states than forground states.