A series of luminescent praseodymium complexes with different aromatic carboxylic acids have been synthesized and characterized. The photophysical properties of these complexes have been studied with ultraviolet spectra, phosphorescence spectra and fluorescence spectra. Ultraviolet absorption spectra show that the praseodymium complexes systems with aromatic carboxylate form the more extensive conjugated systems to be suitable for the distribution of electron in the whole coordination environment, resulting in the energy decrease and red-shifts of ultraviolet spectral bands. Phosphorescence spectra suggest that excited triplet state of aromatic carboxylic acids, which can indicate the energy match and intermolecular energy transfer process between the excited triplet state of ligands and the resonant emissive energy level of Pr ions. The emission spectra of all praseodymium complexes show two emission peaks under the excitation band of 245nm at about 395 and 595nm, respectively, while one peak at about 595nm under 415nm excitation, which attributed to be 1 S 0 → 1 I 6 (395nm) transition and the characteristic emission 1 D 2 → 3 H 4 (595nm) transition of Pr 3+ ion. The 1 S 0 → 1 I 6 transition can be speculated to belong to the transition of charge transfer state, and the 1 D 2 → 3 H 4 can be further proved that there exists an antenna effect in the luminescence of praseodymium with aromatic carboxylic acids. In conclusion, the praseodymium complexes systems can realize the double proton light conversion both in the ultraviolet and visible region, which can be further studied to have potential application.