Adamantane-containing polyesters were prepared from dimethyl 5-adamantylisophthalate and 1,4-butanediol using melt polymerization catalyzed by titanium isopropoxide. The adamantyl group caused a large increase in T-g (of 80 to 142 degrees C) by inhibiting chain segmental motion in these flexible chain polymers. Surprisingly, the copolymer with 25 mol% dimethyl 5-adamantylisophthalate displayed semi-crystalline behavior as confirmed by DSC and X-ray diffraction results. The amorphous copolymers were soluble in chloroform and methylene chloride while the semicrystalline material was not.