The Hallyu K-Pop phenomenon forms an impulsive buying behavior among NCT fans including the members of the Jdozyen Group Order. In this study, the researcher uses the theory of biologist Ludwig von Bertalanffy in the book Little John (2017: 269), namely the Input-Process-Output group communication model. This study aims to analyze how the communication of the NCT fan group in creating impulse buying behavior towards albums and merchandise in the Jdoyzen Group Order in the Line application using descriptive qualitative methods and constructivism paradigm approaches. Data collection was obtained through interviews, participant observation, and literature study by testing the validity of the data using a source triangulation technique that compared the results of interviews with several informants. The results showed that group communication in Jdoyzen's group order members on Line application started from searching for information about NCT's album and merchandise products from the admin and several members, which were then distributed to group chats through two main channels, namely group chat and personal chat. After that, the members showed various responses, expressions, and feedback, and there were even complaints. There are positive and negative responses and expressions. This response formed a discussion process regarding product details, prices, and shipping costs. In the discussion process, there is an element of encouragement and persuasion from both the admin and fellow members to make a purchase, so that some affected members will create a buying behavior that leads to impulsive buying behavior.
Keywords: Group Communication, Fan Groups, Consumer Behavior, Impulsive Buying Behavior