The S-1-S-0 electronic spectra, and the vibrational spectra of jet-cooled 2-pyridone (2PY) and its hydrogen bonded clusters, 2PY-H2O and 2PY dimer, have been investigated by population labeling and various double-resonant vibrational spectroscopies. For bare 2PY, the S-1-S-0 spectrum was measured by laser-induced fluorescence and population labeling spectroscopy. In addition, IR and Raman spectra of the NH stretching vibration were observed in S-0 and S-1. The results led to the conclusion that 2PY has two close lying electronic states in the S-1 region, whose structures are slightly different with respect to the NH group. It was also found that the NH stretching frequency becomes smaller in S-1 than in S-0, indicating that the NH bond strength of 2PY becomes weaker in S-1. The effect of the electronic excitation on the hydrogen bond strength has also been investigated by measuring the NH and OH stretching vibrations of the hydrogen bonded clusters in the two electronic states, and it was found that the hydrogen-bond strength is weaker in S-1 than in S-0. For 2PY dimer, the IR and the Raman spectra of the NH stretching bands showed a clear intensity alternation, confirming its C-2h symmetric structure.