Abstract: Macrocyclic aromatic ester dimer was characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrum (MALDI-TOF-MS) and nuclear magnetic resonance (NMR) spectrum methods. No any more fragment ionization peaks except for the molecular ion peak from the mass spectrum. The structure of macrocyclic dimer was further affirmed by the NMR spectrum through the analysis of chemical shifts. The MALDI-TOF-MS combining and NMR technique were the important tools to characterize macrocyclic aromatic oligomers.