While collaboration is increasingly recognized to be important for research, researchers' collaboration networks are still not adequately recognized as a form of research capacity in the literature. Research is a knowledge creation activity and interpersonal research collaboration networks are important for knowledge cross-fertilization and research productivity. By referring to social network theories, this paper argues that research collaboration networks are a form of research capacity at interpersonal level. It complements capacity building at individual, organizational and inter-organizational levels. However, building research collaborations can be challenging. Three key issues are raised for discussion. First, collaboration networks have nonlinear effect on research productivity. Second, fostering heterophilous communications and maintaining degrees of heterophily can be contradicting and thus challenging. Third, building research collaboration networks proactively requires shift of research management philosophy as well as invention of analytical tools for research management. Debates and solutions with regard to these issues may contribute to the advancement of theory and practice of research management.