Theoretical Study indicates that the HSO center dot center dot center dot HNO complex possesses simultaneously two substantial blue-shifted H bonds: S-H center dot center dot center dot O and N-H center dot center dot center dot O. The blue shift of the S(N)-H stretching frequencies is due to an intricate combination of two shortening effects of the electron density decrease in the sigma*[S(N)-H] and the rehybridization of sp '' S(N)-H hybrid orbitals.