1. High resolution X-ray diffraction data Collecte at 100K on a Smart CCD diffractometer 2. Data refinement by the Hansen-Coppens (2) multipole model 3. Characterization of the chemical bonds and the electrophilic/nucleophilic characters of the two precursors: electron density topological properties and the electrostatic potential 4. Comparaison between the experimental results and the ab initio quantum mechanic calculations for (2) and (3) isolated molecules 5. Theorical calculations for (1) molecule Styrylquinoline derivatives are potent inhibitors of the HIV-1 virus integrase activity (1). The biologically tested molecules contain one aromatic part connected to the quinoline group through different chemical spacers. The most promising molecule in the inhibition of the HIV-1 integrase is the (E)-8-hydroxy-2[2-(4,5-dihydroxy-3-methoxyphenyl)-ethenyl]-7-quinolinecarboxylic acid (1) where the spacer is a C=C double bond. The crystallization of this molecule is particularly difficult giving rise to very small needle-shape crystals which are instable in time. In order to recover the molecular property, we have synthesized and crystallized the two precursors of this molecule: the 3', 4', 5'-methoxy-dihydroxy benzaldehyde aromatic part (2) and the 8-hydroxy-7-quinolinic acid (3).