Superconductivity in transition metal oxides (TMOs) usually favors oxygen-rich compositions, where polyhedral units surround transition metals, minimizing interaction between neighboring atoms. Herein we report a pressure-induced Pnma phase of $\mathrm{Nb}{\mathrm{O}}_2$, identified by first-principles swarm structure calculations, featuring one-dimensional linear Nb chain. The formation of this Nb chain is fundamentally attributed to the interaction of $4d_{x2-y2}$ electrons of adjacent Nb atoms, which contribute the metallic character of $\mathrm{Nb}{\mathrm{O}}_2$. Electron-phonon coupling calculations reveal strong interactions between Nb $4d_{x2-y2}$ states and low-frequency Nb-dominated phonon modes, playing a crucial role in driving the superconducting transition. Remarkably, $\mathrm{Nb}{\mathrm{O}}_2$ can be quenched to ambient pressure and exhibits a superconducting transition temperature ($T_c$) of 20 K, the highest-$T_{\mathrm{c}}$ value reported to date among binary TMOs.

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• Electronic structure
• Pressure effects
• Superconducting phase transition
• Transition metal oxides
• Density functional calculations