A copper phthalocyanine (CuPc) has been encapsulated in silica. The trapping effects were studied comparing the UV-Vis absorption spectra of some CuPc solutions and composites prepared under different conditions. The trapped organic molecules'' stability was monitored during the gelation and drying processes. Leachability test have been carried out with the aim of checking the trapping efficiency. Hydrolysis water of pH = 2 and a molar ratio R _w = 6 mol acid H₂O/mol TMOS leads to a higher CuPc stacking angle homogeneity. The increase of Pc induces a narrower mesopore distribution and helps the stabilization of the composite.