A fully wood-derived ("all-wood"), high-performance photocurable resin has been developed specifically for room-temperature vat 3D printing under low light intensity. The formulations were based on Bisguiacol-F-Diacrylate (DA), a lignin-derived aromatic monomer, and Acrylated Guaiacol (MA) employed as a reactive diluent. To enhance the mechanical and thermomechanical properties, the rheologically optimized formulation (70DA-30MA) was reinforced with Methacrylated Pinewood flour (MP) up to a loading of 10 phr. Rheological analysis confirmed a suitable viscosity for room-temperature printing, with the addition of MP inducing a shear-thinning behaviour. UV-curing kinetics were studied via FT-IR and Photo-DSC to investigate the effect of reactive diluent and filler addition. Morphological analyses (SEM) of the fracture surfaces of 3D-printed samples revealed excellent interfacial adhesion between the polymer matrix and wood flour, thanks to its surface functionalization. Thermal and mechanical properties of composite samples were investigated through DMTA and tensile tests, revealing an increase in the glass transition temperature (Tg) from 38 degrees C to 62 degrees C, accompanied by an increase in Young's modulus and ultimate tensile strength (UTS). These results demonstrate the potential of biomass-derived aromatic monomers and reactive fillers for the fabrication of fully bio-based, advanced 3D composites, bridging the performance gap with traditional fossil-based resins.