The huge success from recent surveys with medium-size wide-field telescopes, such as 2MASS Survey and Sloan Survey, manifest the unique roles of medium-size telescopes in astronomy and astrophysics. The barely started VISTA survey and the new accomplishment of PAN-STARRS are surely continuing the legend of new discoveries. Activities related to the development of medium-size optical/infrared telescope in East Asian region are stimulating. New concepts and technology on telescope optics, structure, and detectors, and even the application of telescope to the extreme sites such as Dome A, Antarctica, pave the roads to the success of sciences in near future. Results from the continued site survey activities in East Asian area imply further opportunities to facilitate new instruments in Ghari area in Qinghai-Tibet Plateau. In the most recent discussions among East Asian Core Observatories Association (EACOA) , it has been recognized that a timely discussion is necessary to formulate the unique science cases, to create new telescope concept, and to formulate teams dedicated to research and development. It is also expected to form close collaborations which will surely accelerate each project. Taking the opportunity of this workshop, we cordially invite ideas and discussions on the unique sciences and developments, and applications on medium-size telescopes. The workshop will be held in Kunming, China during Middle of April, 2013. The workshop will include invited speakers and contributions.