Surface enhanced raman scattering (SERS) of triphenylene (TP) has been recorded on Ag nanoparticles functionalized with the molecular assembler bis-acridinium lucigenine dication (LG) which approaches the adsorbate to the metal surface allowing for its detection. Structural information on the host and the analyte can be extracted from the SERS spectra of LG and LG/TP complex. The acridinium planes in LG are staggered, so cavities into which hydrophobic TP can be allocated are created. Moreover, the orientation of LG with respect to the metal surface changes from tilted to perpendicular when concentration of TP increases. However, perpendicular orientation of TP with respect to the metal surface is preferred according to the in-plane enhanced bands recorded in the SERS spectrum. The dependence of the Raman signal of TP on LG concentration has been checked, and trace concentrations of TP have been detected by this technique which therefore can be used as a chemical sensor of organic pollutants.