The synthesis of photosensitive polymers that contain the triazeno group (Ph-N=N-NR2) as a sensitive unit in their backbone is reported. The synthesis pathway consists of difunctional alcohols incorporating the photosensitive unit that react with diacyl derivatives to give the respective polyesters. Upon irradiation, the photosensitive chromophores both in monomeric and polymeric surroundings are cleaved fast and irreversibly, as shown in photolytic studies and their kinetic evaluations. Thermogravimetrical investigations indicate the loss of nitrogen being the initial thermal decomposition step and exhibit stabilities sufficient for the requirements in applications as photoresists.