Thermal analysis of polyester and polyamides based on vanillic acid derivative — terephthaloyl-bis-(3-methoxy-4-oxy benzoic) acid has been reported. Different behaviours with the appearance of the thermal degradation, stucturization and carbonization stages were detected. Thermochemical behaviour of polymers under investigation revealed that technical lignin derivative — vanillic acid are a promise for obtaining polymer materials with good properties.