Densities of pure N,N-dimethylformamide, N,N-dimethylacetamide, 1,2-dichloroethane, 1,4-dichlorobutane, and 1,6-dichlorohexane were measured at (288.15, 298.15, 308.15, and 318.15) K at pressures up to 20 MPa, and from them, isothermal compressibilities were obtained. Densities for N,N-dimethylformamide or N,N-dimethylacetamide + 1,2-dichloroethane, or + 1,4-dichlorobutane, or + 1,6-dichlorohexane at 298.15 K and at pressures up to 20 MPa were measured, and isothermal compressibilities were obtained.