We consider a relational economy in which economic agents participate in three types of relational economic activities: autarkic activities; binary matching activities; and plural cooperative activities. We introduce a stability notion and characterize stable interaction structures, both in the absence of externalities from cooperation as well as in the presence of size-based externalities. It is shown that institutional elements such as the emergence of socio-economic roles and organizations based on hierarchical leadership structures support and promote stable economic development.