This paper reports on the intercalation of the cationic water-soluble tetrakis(N-methyl-4-pyridyl) porphyrin copper into V2O5 xerogel and the structural and spectroscopic characterization of the obtained products. The preparation procedure is carried out to preserve the anisotropic lamellar structure nature of the xerogel. The X-ray diffraction, FTIR, EPR, and SEM data show the maintenance of the matrix framework during the intercalation, which is consistent with a topotatic reaction, and the formation of nucleation centers promoting the organization of polimeric chains. The results also indicate weak interaction between the host and guest species leading to the formation of an ordered organic-inorganic composite. (C) 2000 Elsevier Science Ltd.