In this paper, which is exploratory in nature, we introduce the concept of dynamic electronic institutions, which from our point of view arise from the convergence of two research areas: electronic institutions and coalition formation. We define dynamic electronic institutions as emergent associations (coalitions) of intelligent, autonomous and heterogeneous agents, which play different roles, and which are able to adopt a set of norms in order to interact with each other, with the aim of satisfying individual goals and/or common goals. These formations are dynamic in the sense that they can be automatically formed, reformed and dissolved, in order to constitute temporary electronic institutions on the fly. This type of institution should be able to adapt its norms and objectives dynamically in relation to its present members (agents). In this paper we introduce some preliminary ideas on how these systems could be developed, and present our first exploratory work. We argue that dynamic electronic institutions are potentially important in open-agent system applications.