Observations of the textures and phase transitions of 4-bromobenzylidene-4'-hexyloxyaniline (6BBAA) and 4bromobenzylidene-4'-pentyloxyaniline (5BBAA) thermotropic liquid crystals were carried out using a polarizing optical microscope under crossed polarizers with a hot stage and high -resolution camera. Using open source TOApy software the thermooptical analysis of the phase diagram for 5BBAA and 6BBAA compounds has been obtained without any additional equipment. To obtain thermooptical analysis plot with help of TOApy three different algorithms have been applied. In this manuscript TOApy software is presented as a tool for the detection of phase transitions difficult to observe by DSC method.