Thin films of single-walled carbon nanotubes (SWNTs) arise as an attractive platform for the development of SWNT based photonics due to their unique optoelectronic properties and compatibility with conventional lithographic processing. However, in earlier days of SWNT field development, the quality of SWNT material was ill-defined, and we will start this talk with a brief discussion of our past efforts on establishing quality control of the SWNT synthesis and purification by utilizing near-infrared spectroscopy (Nano Lett. 2003, 3, 309; JACS 2005, 127, 3439). Next, we will briefly discuss our earlier efforts on development of optoelectronic devices based on SWNT thin films such as infrared bolometer (Science 2006, 312, 413) and optocoupler (Nano Lett. 2008, 8, 2224). In our more recent works the following concepts for the development of the SWNT thin film based optoelectronic devices were tested: i) UV detector based on a vertical heterojunction of a semitransparent film of p-type semiconducting SWNTs (SC-SWNTs) with an energy gap of ~0.7 eV and a wide bandgap semiconductor ZnO (ACS Appl. Mat.&Int, 2017, 9, 37094). ii) Lateral electrochromic devices in which the spatial pattern of the electro-optical modulation can also be controlled by addressing different lateral electrode patterns, so the SWNT thin film can act as an electrically configurable optical medium (Nature Photonic 2013, 7, 459). iii) Vertical electrochromic cell in which the active electrochromic layer is made of a film of semiconducting SWNTs and the counter-electrode is composed of a film of metallic SWNTs with an ionic liquid utilized as electrolyte (Nano Lett. 2016, 16, 5386; Adv. Mater. Interfaces 2018, 5, 1800861). Here, both electrodes support multiple functionalities as transparent conductors, active electrochromic layers, ion storage layers, and act as 3D electric double layer capacitors. Finally, we will discuss single layer MoS₂ which we explored as an optoelectronic gas sensor. In this recent study, red light LED illumination with photon energy matching the direct bandgap of single layer MoS₂ allowed to use induced photocurrent instead of dark current as a tool for NO₂ gas sensing and improve sensitivity of the gas detection to ppb level.