NOVELTY - Preparing synthesis gas and at least an organic, liquid or liquefiable value product, comprises (a) providing a biomass-starting material (1), (b) subjecting the biomass-starting material to digestion, (c) optionally isolating at least a fraction (c1) enriched with aromatics and at least a fraction (c2) depleted with aromatics, (d) feeding the digestion product of step (b) or the fraction (c1) of step (c) into a dealkylating zone (6), (e) removing a discharge from the dealkylating zone and subjecting to separation and (i) at least partially using a stream of step (e) to prepare synthesis gas.    USE - The process is useful for preparing synthesis gas and at least an organic, liquid or liquefiable value product, where the synthesis gas includes carbon monoxide- and hydrogen-containing gas mixture.    ADVANTAGE - The process is cost-effective and provides pure synthesis gas.    DETAILED DESCRIPTION - Preparing synthesis gas and at least an organic, liquid or liquefiable value product, comprises (a) providing a biomass-starting material (1), (b) subjecting the biomass-starting material to digestion, (c) optionally isolating at least a fraction (c1) enriched with aromatics and at least a fraction (c2) depleted with aromatics from the digested material obtained in step (b), (d) feeding the digestion product from step (b) or the fraction (c1) from step (c) into a dealkylating zone (6) and reacting it in the presence of hydrogen and/or steam, (e) removing a discharge from the dealkylating zone and subjecting to separation, to produce at least one organic liquid or liquefiable value product and at least a stream with high content of volatile components lighter than the organic value product, and (f) at least partially using a stream obtained in step (e) with high content of volatile components lighter than the organic value product for preparing synthesis gas.    DESCRIPTION OF DRAWING(S) - The figure shows schematic representation of a process for preparing synthesis gas and at least an organic, liquid or liquefiable value product.    Biomass-starting material (1)    Decomposition product (2)    Aromatics-depleted stream (3)    Aromatics-enriched stream (4)    Dealkylation zone. (6)