The sharp size exclusion endowed to MOFs by their narrow porosity together with their controlled pore chemistry make these materials excellent candidates for selective VOC preconcentration. Importantly, the thickness of MOF films or size of MOF particles can be adjusted to match the decay length of the confined electromagnetic field of LSP. When deployed on SERS substrates, this property allows to optimize the performance of the combined metallic nanostructures and MOF in terms of EM contribution to enhancement of Raman scattering. Furthermore, MOFs can be treated as semiconductor-like light harvesters with reprogrammable optical gaps thanks to their chemical and structural diversity, thus tapping on efficient CM contribution. Research on SERS substrates with carefully tuned MOFs is a promising field that has been progressing over the last decade. In general, there are several aspects that MOFs offer in SERS measurements: (i) MOF natural porosity allows to accumulate the target analytes close enough to the SERS substrate so they can be probed by the confined LSP field, as schematized in Figure . (ii) MOFs can act as a molecular sieve functioning for size-exclusion and offer tunable polar character in the vicinity of the metallic surface. Therefore, for example, moisture-saturation of active sites can be avoiding and/or controlled. (iii) Non-specific interactions and secondary reactions such as oxidation or poisoning of metallic surfaces will affect SERS response. The chemical, thermal, and mechanical stability of MOFs help to prevent those effects. (iv) Enhancing the EM contribution to SERS by the confinement of LSP field though the increased refractive index of MOF (Figure ). (v) By choosing the appropriate MOF-analyte combinations that allows coupling in terms of optical gaps matching HOMO-LUMO levels of the analyte result into a CM with high enhancement factors, close to those reported for EM. As an example of the latter, energy band matching diagrams for ZIF-8 and two Raman-active molecules -Rhodamine 6G (R6G) and Methyl Orange (MO) are shown in Figure . Assuming a 532 nm laser (2.33 eV) is employed as light source for Raman scattering on MO, µPICT transition from HOMO level in ZIF-8 can be expected to take place towards the LUMO level of MO. Additionally, µGSCT transition can also occur given the small difference between the energy of both HOMO levels as well as molecular resonance of MO. Interestingly, this interactions 8 would have negligible effect to the enhancement of Raman signal for the other molecule R6G, since the energy mismatch between ZIF-8 and R6G HOMO-LUMO levels. Nonetheless, this can be reverted if, for example, ZIF-67 is employed instead of ZIF-8. ZIF-67 is an isomorph of ZIF-8 with Zn atoms being replaced by Co and it exhibits its HOMO level at -5.80 eV and LUMO level at -3.81 eV, representing an optical band gap of 1.99 eV. Now, ZIF-67 can actively couple with R6G, but will be inactive for MO. All the different aspects highlighted before contributing to the overall enhancement of the Raman signal in SERS and pairs MOF-analyte can be designed ad-hoc for specific applications.