The possibility of simultaneous characterization of N 2 O and N 2 O van der Waals complexes in supersonic jet expansions is demonstrated for neat N 2 O samples. Room temperature and jet-cooled spectra of the Rydberg transitions 3pπ 1 Δ ←← X 1 Σ + and 3pσ 1 Π ←← X 1 Σ + are presented. Theoretical calculations support the assignment of the Rydberg transitions used. For stagnation pressures above 2 bar, a hitherto unreported broad spectral feature at 84650cm −1 is observed, where calculations predict absorption of the (N 2 O) 2 dimer essentially due to excitation of the 4sσ and 3pπ Rydberg orbitals. Consequences for the use of N 2 O as a precursor for O( 1 D) atoms in reactive scattering experiments are discussed.