Details on the sample fabrication and the electrochemical grafting of the AQ molecular layer are given in the Methods section. Junctions were made in a cross-bar geometry by embedding a ~8 nm-thick AQ grafted molecular layer between two metallic electrodes made of a Ti(2 nm)/Au(50 nm) bilayer 8, 22. Such approach captures the effect of quantum interference and allows an easy integration of the inelastic contribution to transport due to el-ph coupling 15. Within the model the electronic transmission function is calculated by the non-equilibrium Green function formalism (NEGF). Data analysis is developed by using a generic two-site model 12, 14, supported also by DFT calculations. Experimental data can be described by considering interacting quantum transport for electrons 15, 20, 21. Here, we found that many phonon modes with characteristic energies ranging from 5 meV to 200 meV are activated in the molecular layer. Inelastic processes are revealed by the temperature dependence of the zero bias conductance and by the voltage dependence of conductance at low bias and low temperature. Our experiments further show that the QI effect clearly remains visible even in the presence of el-ph interaction. We are hereby able to use the QI effect in the AQ layer to study the el-ph interaction by measuring very large inelastic signals, in agreement with theoretical predictions 15, 18. We realize highly controlled current and conductance measurements of such junctions in a large voltage range and with temperatures varying from 10 to 300 K. In this work we present measurements of short chains of anthraquinone based molecular layers, showing QI effect, embedded in solid-state devices. Besides, the experimental investigation of the low temperature and low energy behavior of quantum interference is lacking. Despite many theoretical works 15, 16, 17, 18 and one experimental result obtained in a slightly different regime 19, the influence of electron-phonon interaction on quantum interference has not been clearly addressed experimentally. Furthermore, a thorough study of the el-ph interaction requires the ability to control the temperature. While single-molecule measurements are challenging for molecules with QI effect since the current signal is close to the typical noise limit in such experiments 3, 4, junctions containing a layer of molecules do not suffer from this problem. In molecules showing QI effect, it has theoretically been predicted that the inelastic contribution to the current can be very significant and may even exceed the elastic part. The quantum interference (QI) transport regime is achieved whenever two molecular orbitals coupled to a metal lead contribute simultaneously to charge transport, then multiple orbital pathways can interfere destructively 10, 11, 12, 13, 14. anthraquinone (AQ) based molecular junctions 1, 2, 3, 4, 5, 6, 7, 8, 9. In certain molecules, the elastic current is dramatically suppressed due to destructive quantum interference, as recently demonstrated experimentally and theoretically for e.g. However the inelastic signal from el-ph interaction is usually small compared to the elastic (non-interacting) contribution to the current. Molecular junctions are ideal test systems for studying el-ph interaction, since the influence from individual vibrational modes with well-defined energies can be observed in the current running through the device. Interaction between electrons and phonons (el-ph) is an ubiquitous process with fundamental as well as practical importance in systems ranging from superconductors to power dissipation in electronic devices.