Stages 4-6 FeCl3-graphite intercalation compounds (GIC's) have been prepared by an ordinary two-bulb method, and FeCl3-IBr-graphite bi-intercalation compounds (GBC's) are synthesized by holding the FeCl3-GIC's in the saturated vapor of IBr. The x-ray diffraction patterns of the FeCl3-IBr-GBC's obtained from stages 4, 5, and 6 FeCl3-GIC's give the stacking sequences as G(FeCl3)GG(IBr)GG(FeCl3)G, G(FeCl3)GG(IBr)GGG(FeCl3)G, and G(FeCl3)GG(IBr)GG(IBr)GG(FeCl3)G, respectively, where G, (FeCl3), and (IBr) refer to the graphite, FeCl3, and IBr layers, respectively. The multi-intercalation of H2SO4 into the FeCl3-IBr-GBC's synthesized from stages 4 and 6 FeCl3-GIC's occurs at all the vacant galleries of the GBC's at the same time. In contrast, the multi-intercalation of H2SO4 into the FeCl3-IBr-GBC obtained from the stage 5 FeCl3-GIC takes place in two processes. The first multi-intercalation occurs at the gallery adjacent to the bi-intercalated IBr layer, and the stacking sequence of the resulting graphite multi-intercalation compound is determined to be G(FeCl3)GG(IBr)G(H2SO4)GG(FeCl3)G, where (H2SO4) refers to the H2SO4 layer. The second multi-intercalation occurs at all the rest of the vacant galleries.