Recently, we have succeeded in synthesizing thiophene derivative compounds that show chemosenser behavior with several metal cations by synthesizing 2,2'-bithiphene-5-carbaldehyde and propane-1,3-diamine for synthesis of compounds.1 When the compound was mixed with various matal cations, such as Na(I), Cu(II), Ca(II), Ca(II), Zn(II) Co(III), Ba(II), Fe(II) and Fe(III), addition of Fe (III) showed strong fluorescence enhancement proportional to the concentration of Fe(III) as shown in Fig.1. In this study, we investigated the optimized structures of ligand compound and metal ion complexes through the quantum chemical calculation methods, such as B3LYP and LCgau-B97 which we recently developed.2 The quantum chemical analysis of the experimental results were carried out by calculating the uv-visible spectra and the applicability of the quantum chemical method to this field was examined.