Continuous carbon nanotube (CNT) yarns can be self-assembled by drawing them from superaligned CNT arrays, resulting in yarns up to 30 cm in length. Heating the yarns at high temperatures enhances their strength and conductivity. These yarns, composed of parallel CNT threads, can be controlled in size by the tool tip used for pulling. The yarns can be used to create macroscopic devices, such as light-emitting filaments and polarizers. When used as a light filament, the CNT yarn emits incandescent light and shows increased conductivity and tensile strength after prolonged use, suggesting a welding effect at connection points. The CNT polarizer, made by aligning yarns, can polarize light and function in the ultraviolet range, with a polarization degree of 0.92. The study suggests that CNT yarns, after heat treatment, can be woven into macroscopic objects for various applications, such as bulletproof vests and electromagnetic wave shielding materials. The research was conducted by Kaili Jiang, Qunqing Li, and Shoushan Fan at the Tsinghua-Foxconn Nanotechnology Research Center, Beijing, China.Continuous carbon nanotube (CNT) yarns can be self-assembled by drawing them from superaligned CNT arrays, resulting in yarns up to 30 cm in length. Heating the yarns at high temperatures enhances their strength and conductivity. These yarns, composed of parallel CNT threads, can be controlled in size by the tool tip used for pulling. The yarns can be used to create macroscopic devices, such as light-emitting filaments and polarizers. When used as a light filament, the CNT yarn emits incandescent light and shows increased conductivity and tensile strength after prolonged use, suggesting a welding effect at connection points. The CNT polarizer, made by aligning yarns, can polarize light and function in the ultraviolet range, with a polarization degree of 0.92. The study suggests that CNT yarns, after heat treatment, can be woven into macroscopic objects for various applications, such as bulletproof vests and electromagnetic wave shielding materials. The research was conducted by Kaili Jiang, Qunqing Li, and Shoushan Fan at the Tsinghua-Foxconn Nanotechnology Research Center, Beijing, China.