A new method for the synthesis and film deposition of nonvolatile aromatic lanthanide(III) carboxylates by li.-and exchange reaction between the starting volatile components in the gas phase was proposed. The complexes Ln(BZ)(3) (Ln = La3+, Tb3+, Lu3+; HBz = benzoic acid) were synthesized by gas-phase ligand exchange reaction between the volatile Ln(Thd)(3) and HBz (HThd = 2,2,6,6-tetramethylheptane-3,5-dione). The composition of the complexes was confirmed by elemental, thermal, IR-spectroscopic, and photoluminescence analyses and, in the case of lanthanum and lutetium complexes, by H-1 NMR.