The roll-to roll coating (R2R) is one of the most important processes in developing the flexible devices which are mainly used in the near future in industries of display, battery, touch panel and even textile because it is highly suitable to produce the devices at a high speed and at low cost using flexible webs such as polymer films, thin glasses or metal foils. When we make the flexible devices, some properties of electrical conductance and barrier to water vapor should be obtained up to certain specific values depending on the reliability of products and need of manufactures. We have built up a coating testbed at Korea Research Institute of Chemical Technology (KRICT) where several types of R2R coaters are operated at a pilot scale with very similar conditions to those of production factories. For example, a R2R wet coater can be operated with changing a coating head depending on coating solution viscosities and coated thickness. The R2R sputter is used to prepare the ultra-thin layers as thin as a few nanometers on webs for preparing the transparent electrical conducting or ultra-barrier films using ITO or silicon as target material, respectively. The R2R CVD machine has been used for obtaining the insulation and barrier layers with a dense structure at a modest coating speed. In addition, the instrument such as permeability tester, 3D profiler of surface, adhesion tester, etc is also equipped for measuring and testing the properties of the functional films. In this special session to honor Prof. S. C. Kim from whom I have learned the deep insight into polymers as well as the right ways in life, I will present the recent activities of the coating testbed and database on functional films, especially focusing on the results from the developments of the functional optical films in terms of substrate film properties, coating materials and process conditions. Keywords: Coating, Roll-to-roll, Flexible Device, Database, Barrier, Electrical Conductance