In temperature interval 293-523 K the thermochromic effect in the films of sulfate-doped polyaminoarenes (polyaniline, polyorthotoluidine, and polyorthometoxyaniline) and their composites with elastic polyvinyl alcohol (PVA) matrix has been manifested and investigated. On the base of electronic spectroscopy, thermogravimetry, and specific resistance temperature dependence data it is shown that changes in electron transition energy and film's optical density are caused by changing in macrochain conformation and connected with electronic properties of polymers. Thermochrom effect reserves in composite polyaminoarene-PVA films.