The solubility of selected polynuclear aromatic compounds (anthracene, phenanthrene, carbazole, fluorene, dibenzothiophcne, and dibenzofuran) in three N-substituted amide systems (N,N-dimethylacetamide, N-methyl-2-pyrrolidinone, N-methyl-epsilon -caprolactam) has been measured by a dynamic method over the whole concentration range. In the case of N-methyl-epsilon -caprolactam systems the measurements were carried out from T = 280 K up to the melting temperatures of the aromatic compounds, because of a rapid increase of viscosity resulting in glass formation in the supercooled liquid phases. The incongruently melting compounds were found to exist only in the systems with carbazole. The other systems were simple eutectics. To estimate the activity coefficients, the liquidus curves were approximated with the Wilson, Redlich-Kister, NRTL, and UNIQUAC equations. For all calculated results the root-mean-square deviations of solubility temperatures vary from 0.1 K to 2.8 K, depending on the equation used.