Supplementary Material (ESI) for Organic and Biomolecular Chemistry This journal is © The Royal Society of Chemistry 2006 Molecular Fluorescent pH-Probes Based on 8-Hydroxyquinoline Stefan Kappaun, a Tanja Sović, a Franz Stelzer a , Alexander Pogantsch, b Egbert Zojer,* b,c Christian Slugovc* a a Institute of Chemistry and Technology of Organic Materials (ICTOS), Graz University of Technology, Stremayrgasse 16, A-8010 Graz, Austria b Institute of Solid State Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria c School of Chemistry and Biochemistry, Georgia Institute of Technology, 770 State Street, Atlanta, GA 30332-0400, USA Electronic Supporting Material Compounds under investigation N O N O N O S S 3 4 5