Telechelic oligosiloxanes are obtained either via ring opening polymerization of polycyclodialkylsiloxane or via hydrosilylation with a alpha,omega -bis hydrosilane oligosiloxane or via condensation between a alpha,omega -bis hydroxy oligosiloxane and an appropriated chlorosilane. This study investigates the synthesis of a alpha,omega -bis anhydride oligosiloxane via hydrosilylation of bicyclo[2.2.1]hept-5-ene-endo-2,3-dicarboxylic anhydride with alpha,omega -bis hydrosilane oligosiloxane in the presence of a Platinum catalyst. Using a Pt catalyst induced a long reaction time and especially an important increase of average molecular weight. Another method of synthesis in two steps was then set up: condensation of exo,5-(dimethylchlorosilyl)bicyclo-[2.2.1]heptane-endo-2,3-dicarboxylic anhydride with alpha,omega -bis hydroxy oligosiloxane which leads to the expected oligosiloxane, rapidly and quantitatively. Thermal properties have also been investigated alpha,omega -bis anhydridr oligosiloxane may take part in the synthesis of block copolymers.