Thebinarycomplexesofeuropiumwithbenzoicacidanditsderivatives(phthalicacid,m-phthalicacid,o-aminobenzoicacid,salicylicacid,andsulfosalicylicacid)weresynthesizedandtheircompositionswereidentifiedbyelementalanalyses.UVandIRofthecomplexeshavebeeninvestigated.TheUVspectraindicatedthatthecomplexes'ultravioletabsorptionweremainlytheligands'absorption.TheIRspectrashowedthattheIRspectraofcomplexesaredifferentfromthoseoffreeligands.Thefluorescencepropertiesofthemwereinvestigatedbyusingluminescencespectroscopy,theresultsshowedthatonlythreecomplexesappearasbetterluminescence,theywereEu-benzoicacid,Eu-m-phthalicacidandEu-phthalicacid,whiletheothersexhibitedtheligands'widebandemission.