New experimental data of H-E and V-E Of seven polyether and polyamine + propan-1-ol mixtures have been obtained and the results are compared with an extended version of the extended real associated solution model (ERAS) model which takes into account a multiple cross-association of self-associating alkanol molecules with different centers of the polyether or polyamine molecule represented by oxygen atoms or NH2/NH-groups in these molecules. The multiple cross-association (MCA)-ERAS model accounts also for possible self-association of the polyethers and polyamines. The model is able to describe the excess properties by adjusting simultaneously a few parameters to the experimental H-E and V-E data. It turns out that the introduction of multiple cross-association is necessary to obtain an adequate description of the excess properties.