By introducing molecular aborber/emitter nano-films into the dielectric layer of a light-absorbing MIM metasurface, a molecular assembled metasurface is formed with the optical phenomena of weak and strong coupling of the molecular absorber/emitter and the metasurface mode. It provides a precise control of the spectral overlap between the molecular absorption band and the metasurface resonance . Furthermore, it was demonstrated that the Kirchhoff's law of thermal radiation is directly applicable to the absorption spectra of the molecular vibration coupled to the metasurface resonance. In other words, the radiation spectrum is equivalent to that of optical absorption regardless the weak or strong coupling with the MIM mode. The molecular vibrational spectrum has narrow bands as compared to the conventional MIM metasurfaces radiation and even narrower than that of mid-IR light emitting diodes (LEDs). The radiation wavelength of such molecular emitters/radiators matches exactly the molecular fingerprint spectral region by definition.