Fourier transform infrared spectra of indole in carbon tetrachloride solutions were recorded. The spectroscopic data indicate that even at relatively low concentrations, the solute forms molecularly associated pairs through N-H...π hydrogen bonding. Both NIR data and AM1 calculations show that, in comparison with the monomeric ν(N-H) mode, the anharmonicity of the ν(N-H...π) mode decreases, and that of the dimeric ν(N-H) mode slightly increases. The anharmonicity constants for these modes are calculated on the basis of the NIR data, and the changes of the ν(N-H) potential upon N-H...π hydrogen bonding are quantitatively studied. The orientational dynamics of monomeric and associated indole species are studied within the framework of the time correlation function formalism. The period of essentially free rotation in the condensed phase reduces from 2.3ps for the monomeric indole to 0.4ps for the proton-donor molecule within the dimer.