DNA has evolved to be a type of unparalleled material for storing and transmitting genetic information. Much recent attention has been drawn to translate the natural specificity of DNA hybridization reactions for information storage in vitro. In this work, we developed a new type of tubular nucleic acid (TNA) by condensing DNA chains on the surface of one-dimensional carbon nanotubes (CNTs). We find that DNA interacts with CNTs in a sequence specific manner, resulting in different conformations including helix, i-motif, and G-quadruplex. Atomic force microscopic (AFM) imaging revealed that TNAs exhibit distinct patterns with characteristic height and distance that can be exploited for two-dimensional encoding on CNTs. We further demonstrate the use of TNA-CNT for information storage with visual output. This noncanonical, DNA hybridization-free strategy provides a new route to DNA-based data storage.