[en] Highlights: • Para-aromatic dicarboxylates could be the organic anodes in K-ion battery. • Satisfactory rate and cyclic capability were achieved in K-ion battery. • Specific capacity of average ~190 mAh g⁻¹ was obtained for 100 cycles. Two small organic molecules, namely potassium terephthalate (K₂TP) and potassium 2,5-pyridinedicarboxylate (K₂PC), were newly exploited as the highly efficient organic anodes in K-ion batteries. Both K₂TP and K₂PC exhibited the clear and reversible discharge and charge platforms in K-ion half cells, which were resulted from the redox behavior of organic para-aromatic dicarboxylates. The satisfactory and reversible specific capacities were realized in the K₂TP- and K₂PC-based K-ion cells, with average values of 181 and 190 mAh g⁻¹ for 100 cycles, respectively. The currently-obtained achievement of organic anodes could make a forward step for the further development of rocking-chair K-ion batteries.