AbstractUsing the Gibbs free energy of mixing relation of Flory and Huggins with a concentration‐dependent interaction parameter one can calculate quasi‐binary phase diagrams for solvent‐polymer systems. If the polymer has a very asymmetric molecular weight distribution, separation into three‐liquid‐phases occurs which may result in a cloud‐point curve without stable critical point. In the latter case the spinodal does not touch the stable branches of the cloud‐point curve and the coexistence curves show marked bends and kinks. These phenomena could be qualitatively verified by experiments on the system cyclohexane‐polystyrene. The phase‐volume ratio method for the determination of consolute states itself clearly indicates when situations prevail precluding