The potential of combining continuous flow and mechanochemistry for biomass valorization was explored in this work. Vanillin production employing isoeugenol and vanillyl alcohol as sustainable biomass-derived feedstocks was chosen due to the relevance of this flavoring molecule and the current need to find alternative starting materials to industrially used petro-based compounds. The combination of continuous flow and mechanochemistry led to outstanding results in terms of conversion, selectivity, and yield of vanillin by performing the reaction in the absence of catalysts from the lab to scale-up results (a 0.5−1 L DYNO-MILL Multi Lab reactor). The transformation of vanillyl alcohol toward vanillin was additionally performed in a DYNO-MILL Research Lab, a laboratory scale flow mechanochemical reactor (Willy A. Bachofen AG, Switzerland), observing optimum values of conversion, selectivity, and yield of the product of interest.