In this study, we have investigate the molecular -metasurface coupling with different type and functional group molecules. We revealed the effect that not only the molecular transition moment, but estimated molecular number of the vibrational modes √ N clearly affects the coupling efficiency. T he p resented i dea and analysis can be applied not only for polymer materials but also monomer molecules. By controlling the coupling between molecular vibration and MIM metasurfaces is should be possible to realize the platform for detection of small/trace amounts of molecular species, on-demand mid-IR light sources of volatile organic compounds and to monitor chemical reactions on a molecular level . One particular application which could benefit from the proposed spectroscopic platform is hydrogen sensing where low amount of H + and H + should be detected in the volume of phase-change material Y, WO 3 , metals Pd, Pt, or their alloys . Strong coupling between MIM structural resonance and molecular vibration is a new unexplored frontier for detection of trace amounts of materials/molecules.