A versatile approach to the synthesis of novel polyamidoamine (PAMAM) side-chain dendritic polyester (SCDPE) possessing azobenzene motifs in the polymeric core is described and displayed reversible cis-trans (E/Z) isomerization upon exposure to UV light. A polymerization reaction was conducted in solution using ester-terminated PAMAM dendritic diol (1a, G 3.5) and azobenzene dicarboxylic acid chloride in the presence of triethylamine. PAMAM dendritic diol la as well as SCDPE (1) were thoroughly characterized by means of IR and NMR (H-1 and C-13) spectroscopies. The intrinsic viscosity of 1 at 36 degreesC in CHCl3 was found to be 0.38 dl/g.