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The t4N quadrupolar relaxation time for pyrrole as the pure liquid and in solution in 1,4-dioxan, pyridine, 3,5-1utidine and 2-fluoropyridine has been determined from the line-shape analysis of the imido proton magnetic resonance signal. The dependence of the line shape on solute concentration and temperature was studied and the activation parameters for molecular reorientation determined. INTRODUCTIONNuclear magnetic relaxation measurements can provide valuable information on molecular motions and interactions in liquids. However, the main difficulty in interpreting such information lies in the separation of the observed relaxation time into contributions from different mechanisms (e.g. dipole-dipole, scalar, spin-rotation) which arise from both intra and inter-molecular motions. The problem is considerably simplified [1, 2] if the nuclei under study are relaxed by the quadrupole mechanism, since this can be two or three orders of magnitude more efficient than competing mechanisms, including relaxation by dissolved oxygen. Furthermore, quadrupole relaxation is normally governed by intramolecular motions only, since the contributions of inter-molecular motions to the local electric-field gradients are very small and separation of translational effects is not needed.Many papers have dealt with studies of molecular motions in pure liquids but so far much less attention has been paid to strongly interacting systems such as those involving hydogen-bonded or charge-transfer interactions [3]. Mixtures of hydrogen-bonded liquids offer an interesting possibility for these studies.