The development of the Cd1-x-yMnyHgxTe and Zn1-x-yMnyHgxTe solid solutions which has been proposed for infrared photoelectric devices with predetermined spectral characteristics has made significant progress as they are a narrow band gap materials with direct optical transition. To configure high-quality heterostructure films, lattice-matching growth is required. For these purposes it is important to clarify the relatively wide regions of instability and immiscibility, which restricts applications of these materials. In spite of the lattice constants being almost identical for the two limiting (binary) cases of CdHgTe (6.48Å for CdTe and 6.46Å for HgTe), the metallurgical interface is usually enriched with structural defects, in particular, mismatch dislocations, elastic deformations, gettered impurities, etc. This results in the significant changes of thermodynamics stability conditions thin quaternary films. This paper presents calculations of spinodal and binodal isotherms of Cd1-x-yMnyHgxTe and Zn1-x-yMnyHgxTe solid solutions and their pseudomorphic thin films on the basis of the delta-lattice parameter model. We used in this work ternary compound Cd1-yZnyTe and Cd1-yMnyTe as substrate for growth films. The novelty of the approach consists in the consideration of mismatch dislocations in elastic energy relaxation.