A polyimide synthesized from 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA) and ethylene diamine (EDA) was evaluated as a new anode material for sodium ion batteries (SIB). The polyimide delivers a discharge specific capacity of 140 mA h g⁻¹ at an average potential of 2 V vs. Na⁺/Na with an initial coulombic efficiency of 97.6% and exhibits an excellent cycleability with a capacity retention of 90% over 500 cycles. A full SIB with polyimide anode and Na₃V₂(PO₄)₃/C cathode and Na₄Fe(CN)₆/C cathode was proposed.