The annual conferences at MIT on spectroscopy and its applications provided a market where consumers and producers of spectrum analysis of substances could meet and exchange their knowledge, skills, and products on spectrum analysis. In ten conferences between 1933 and 1942, George Russell Harrison, the first director of the MIT Spectroscopy Laboratory and the organizer of the conferences, emphasized the application of spectroscopy to diverse fields of sciences and to practical problems in industries. Accordingly, conferences attracted not only physicists and astronomers who traditionally made uses of spectroscopes as research tools, but also biologists, medical doctors and research workers in government agencies and industries who were rather new-comers in the field. The close examination of conferences will show that the conferences stimulated self-awareness of applied spectroscopy as a specialized field and applied spectroscopists as a group.Then, why did these conferences emphasize applications of spectroscopy? I will show three factors influenced on Harrison’s emphasis on application: declining interests in atomic spectroscopy in the early 1930s; the Great Depression society which blamed science for its economic difficulty and unemployment; the 1930s’ MIT where application and cross-disciplinary research were encouraged.