This work presents our investigations of mezomorphic properties of two
polymorphic liquid crystals, namely, 4-nonyloxy-4-butoxyphenyl benzoa
te and N-(-4-heptyloxybenzylidene-4-butylaniline) in a wide temperatur
e range, particularly, in the phase transition regions. By means of an
original Experimental method. the heterophase regions and also the ph
ase transition temperatures have been determined for these materials w
ith high accuracy. These phase transition intervals have been analyzed
using a mean field model.