The high value-added products such as alkyl substituted phenols (A-Ps) are very important from lignin-derived feedstocks. Herein, the selective conversion of guaiacol, an important chemical of lignin-derived bio-oil, to A-Ps over hydrothermally synthesized bulk MoS2 (HT-MoS2) was examined under supercritical methanol conditions without any gaseous hydrogen input. HRTEM confirms the formation of MoS2 with the nanosheet-like structure and XPS analysis exhibited the presence of Mo5+ and S22- species which are likely the active species for demethoxylation (DMO) and alkylation of guaiacol. The possible reaction pathways along with their plausible intermediates of guaiacol conversion are proposed. The HT-MoS2 catalyst can be reused up to 4 catalytic runs without loss of its catalytic activity.