Crystalline lanthanide terephthalates, Ln2bdc3‧nH2O (Ln = La–Lu, excluding Pm), were synthesized using a surfactant-free, ultrasound-assisted method. This approach yielded microcrystals with diverse shapes and sizes ranging from 2 to 10 μm. Notably, under these conditions, lutetium terephthalate uniquely crystallized as Lu2(1,4-bdc)3·2.5H2O, while the remaining lanthanides formed tetrahydrate terephthalates, Ln2bdc3‧4H2O (Ln = La–Nd, Sm–Yb).