AbstractRecently, 5‐hydroxymethyl furfural (5‐HMF) became into the spotlight as one of the most promising biorenewable platforms available from carbohydrates. Among other versatile derivatives of 5‐HMF its dimer 5,5′‐(oxy‐bis (methylene)) bis‐2‐furfural (OBMF) was recognized as a useful building block for the production of polymers and pharmaceuticals. Herein we explored the synthesis of OBMF under solvent free conditions applying vacuum as a green tool for water removal. Several readily available acidic resins, silica gel supported inorganic acid, acidic zeolites and Lewis acids were studied as promoters for this transformation. Under these conditions, SiO2/CF3SO3H exhibited the best performance allowing the synthesis of OBMF in 55 % yield in only 1 min reaction time. Similar results were achieved using Amberlyst 15 and SO2/PPA resulting in 51 % yield in 20 min and 46 % yield in 10 min, respectively.