A new intercalation compound,Fe0.81PS3(4-aminopyridineH)0.38, issynthesized by the direct reaction of4-aminopyridine with layered FePS3 inthe presence of acetic acid.From the XRD results it was found that there aretwo phases (Phase I and Phase II)in this intercalation compound and that4-aminopyridines as the guests adopt twodifferent orientations between theinterlayer region of the host (FePS3).In one of them with the latticeexpansion (Δd) of 6.0 Å thering plane of the guest is perpendicular to thelayer and in the other with Δd of3.4 Å the ring plane of the guest is parallel tothe layer of the host. The IR spectraimply that the inserted guests take theprotonated form to maintain the charge balanceof the intercalation compound.Magnetic measurements indicate thatFe0.81PS3(4-aminopyridineH)0.38 exhibitsparamagnetism in the range of measurementtemperature (1.8 ∼: 300 K),where the magnetic behavior is wellin agreement with the Curie-Weiss Lawabove 55 K.