In this oral presentation, purification and enrichment of semiconducting single-walled carbon nanotubes (sc-SWCNTs) will be reported and discussed. Conjugated polymer extraction (CPE) process was developed and it was found that a trace amount of polar solvents was able to boost the enrichment yield drastically. We provide insights on CPE by demonstrating that a conjugated polymer having a hydrophobic backbone and hydrophilic side chains provides near full recovery (95%) of sc-SWCNTs using a multi-extraction protocol. This polymer, poly(9,9-bis(2-(2-(2-methoxyethoxy)ethoxy)ethyl)fluorene-alt-pyridine-2,5) [P(FEt3M-Py-2,5)] was designed and synthesized in our laboratories. The resulting hydrophilic SWCNT dispersions demonstrate long-term colloidal stability, making them suitable for ink formulation and high-performance thin-film transistors (TFT) fabrication. As a result, the enriched sc-SWCNTs demonstrated application in high-performance fully ink-jet printed TFT [ACS Nano 2018, 12, 2, 1910–1919]. We also developed a novel indigo-fluorene-based copolymer (PFIDBoc) that has been designed to selectively enrich sc-SWCNTs with excellent purity (>99.9%) yet contain a latent function in the form of a tert-butoxy (t-BOC)-protected amine that can be later revealed and exploited for carbon dioxide gas sensing. The enriched sc-SWCNTs demonstrated TFT-based CO2 gas sensing application with up to ∼5.4% sensitivity between 400 and 2000 ppm in air with a relative humidity of ∼ 40% [ACS Sensors 2020, 5, 2136-2145].