Recent research shows that preexisting network structure constrains the formation of new interorganizational alliances. Firms that are poorly embedded in a network structure are less likely than richly embedded firms to form alliances, because they lack informational and reputational benefits. This study examines the types of ties that poorly embedded firms can form to overcome the constraints that their structural positions impose, in turn helping to explain how firms' actions can transform existing network structures. We argue that poorly embedded firms are more likely to participate in ties characterized by social asymmetry than in ties characterized by structural homophily. We analyze the terms of trade that socially asymmetric partners negotiate for alliance governance and discuss how such alliances influence network dynamics. To test our arguments, we use longitudinal data on the alliance activities of 97 global chemical firms from 1979 to 1991.