Analyzing data on utility patents from 1975 to 2002 in the careers of 35,400 collaborative inventors, this study examines the influence of brokered versus cohesive collaborative social structures on an individual's creativity. We test the hypothesis that brokerage - direct ties to collaborators who themselves do not have direct ties to each other - leads to greater collaborative creativity. We then test interaction hypotheses on the marginal benefits of cohesion, when collaborators have independent ties between themselves that do not include the individual. We identify the moderators of brokerage and argue for contingent benefits, based on the interaction of structure with the attributes, career experiences, and extended networks of individuals and their collaborators. Using a social definition of creative success, we also trace the development of creative ideas from their generation through future use by others. We test the hypothesis that brokered ideas are less likely to be used in future creative efforts. The results illustrate how collaborative brokerage can aid in the generation of an idea but then hamper its diffusion and use by others.