Molecular association of liquid crystalline 4,4’-pentylcyanobiphenyl 5CB), 1-p-cyanophenyl-4-parameters of dimerization process have been obtained for nematic pentyl-cyclohexane (5CH) 2-p-cyanophenyl-5-pentylpyridine(5Py) was studied in bulk, solutions and inert matrices at 77-330K by low temperature reflection IR-spectroscopy and isothermal Calve calorimetric methods. The thermodynamic and kinetic mesophase. The factors effected the dimer stability were considered.