This chapter tests two ways of overcoming uncertainty about relationality – having potential collaborators directly communicate how they will relate to each other, and using third parties such as matchmakers and boundary spanners. Both are useful for creating valuable new collaborative relationships, especially between people who begin as strangers. In addition, this chapter also presents evidence showing the impact of new collaborative relationships on strategic decision-making. Data in this chapter come from a variety of national surveys, field experiments, and case comparisons.