Supporting Information A Neutral Fe(III) Compound Exhibiting A Two-Step Spin Transition and Dielectric Anomalies Zhaoyang Li, a,b Jingwei Dai, a Kevin J. Gagnon, b Hongling Cai, c Hanhua Zhao, b Takashi Yamamoto, d Yasuaki Einaga, d Shinji Kanegawa, a Osamu Sato,* a Kim Dunbar* b and Rengen Xiong c a Institute for Materials Chemistry and Engineering, Kyushu University 6-1 Kasuga-koen, Kasuga, Fukuoka,816-8580, Japan. Fax: +81 92 5837787; Tel: +81 92 5837787; E-mail: sato@cm.kyushu-u.ac.jp b Department of Chemistry, Texas A&M University, P.O. Box 30012 College Station, TX 77842-3012 United States. Fax: +1 979 8457177; Tel: +1 979 8455235; E-mail: dunbar@mail.chem.tamu.edu c Ordered Matter Science Research Centre, Southeast University, Nanjing 211189, China. d Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Yokohama, Kanagawa 223-8522, Japan. Tables/Figures Captions: Table S1 Crystallographic data from Mo(Kα) and synchrotron X-ray diffraction studies of compound 1 at variable temperatures. Scheme S1 Schematic illustration for the deprotonation of the ligand. Table S2 Bond distances of compound 1 selected for X-ray diffraction. Table S3 Bond distances for 1 from synchrotron diffraction at different temperatures. Table S4 Hydrogen bond distances of compound 1 at variable temperatures (Å and °) from synchrotron X-ray diffraction. Fig. S1 Variable-temperature IR for compound 1 at 110 K, 260 K and 300 K. Fig. S2 Packing diagram for 1 along c axis. Electronic Supplementary Material (ESI) for Dalton Transactions This journal is © The Royal Society of Chemistry 2013