Biosourced eugenol-based polymer networks have a potential functionality for antibacterial coating applications. The presence of carvacrol, a phenol compound, improves these properties. However, the relationship between the network structure and the macroscopic thermomechanical behavior is not known for these biopolymers. Thus, this work details a robust study of this relationship through a multiscale experimental approach combining Dielectric Spectroscopy, Dynamic Mechanical Analysis, tensile testing, and Time Domain Double-Quantum proton Nuclear Magnetic Resonance (DQ H-1 NMR). It was shown that carvacrol has an influence on the molecular mobility of the materials. Namely, it induces the appearance of a shouldering on the. relaxation and a diminishing of the main molecular alpha relaxation, T-a. More surprisingly, up to 20% wt, carvacrol increases the elastic E' and Young's E moduli. This observation can be interpreted as an increase of the crosslink density of the networks. Time Domain DQ H-1 NMR shows that the residual dipolar coupling constant also increases. Thus, carvacrol seems to act as both a thermal plasticizer and mechanical reinforcement, which may seem to be antagonistic trends. For carvacrol contents over 20% wt, these properties diminish because of a saturation of this molecule in the networks and the onset of a phase separation. By combining the aforementioned techniques, it was proven that carvacrol linearly increased the measured crosslink density and thermomechanical properties by physically bonding to the networks through pi-pi interactions. These interactions would act as physical crosslinks. This work demonstrates that by correlating the results of various multiscale experimental techniques, a better comprehension of the structure-property relationship can be established for biobased functional polymer networks.