<p><i>π</i>-conjugated polymers (CPs) hold great promise for optoelectronics, energy, and biomedicine, yet bioinspired folded architectures remain underexplored due to limited coupling strategies. Here, we report a scalable synthesis of helical polymer nanotubes via homogeneous Suzuki-Miyaura cross-coupling. Their helical conformation is stabilized by electrostatic repulsion between heteroatoms or intramolecular hydrogen bonding, confirmed by AFM, single-crystal X-ray diffraction, CD spectroscopy, and theoretical modeling. The nanotubes (∼5 nm in length) feature hydrophilic, electron-rich lumens and hydrophobic alkyl exteriors, enabling spontaneous insertion into lipid bilayers. They display distinct, pore-size-dependent transport: wider pores facilitate glucose permeation, while narrower channels with defined coordination sites show selective K⁺ transport. K⁺ selectivity was validated through vesicle-based kinetics and symmetric/asymmetric bilayer lipid membrane (BLM) assays. Notably, the F3 system achieved a K⁺/Na⁺ selectivity ratio of 26.8 in asymmetric BLMs. This work introduces a new class of aromatic helical polymers and highlights the role of coordination site density in ion selectivity. <i>π</i>-conjugated helical polymers are demonstrated for the first time to exhibit both ion selectivity and small-molecule transport, offering a blueprint for designing artificial K⁺-specific nanopores with bio-medical potential, especially for treating channelopathies.</p>