1,2-dimethyl-3-n-butylimidazolium (DMBI) tetrafluoroborate was electrochemically characterized at a graphitic paper working electrode. Cyclic voltammetry indicated reversible cationic intercalation of the graphitic paper. X-ray powder/thin film diffraction measurements of intercalated graphitic paper gave one primary diffraction peak at 3.44671 Angstrom. In addition, detailed diffraction studies revealed several additional reflections at 0 0 1 positions. The X-ray diffraction results are consistent with a DMBI x 1 C intercalate that has a c axis of 10.34013+/-0.0051 Angstrom and a resulting c axis expansion of 6.98 Angstrom. This result suggests that the plane of the five membered imidazolium ring is lying nearly parallel to the graphite sheets. (C) 2003 The Electrochemical Society.