Vinyl-functionalized phenanthroimidazole-based monomers were synthesized and their thermal, optical, photophysical, and electrochemical properties were investigated. The monomers exhibited high thermal stability with 5% weight loss temperatures ranging from 315 to 386 degrees C. Solid state ionization were found to be comparable (5.56-5.62 eV). The number average molecular weight of the polymerization product of monomer containing substituent at phenyl rings linked to C-2 position of imidazole ring was found to be 213000 Da. The values of activation energy for self-polymerization of monomers varied in the range from 86.6 to 143.8 kJ/mol (estimated by Ozawa method), and from 87.8 to 148.0 kJ/mol (estimated by Kissinger method).