Abstract Community coalitions depend on their members to synergistically pool diverse resources, including knowledge and expertise, community connections and varied perspectives, to identify and implement strategies and make progress toward community health improvement. Several coalition theories suggest synergy is the key mechanism driving coalition effectiveness. The Community Coalition Action Theory (CCAT) asserts that synergy depends on how well coalitions engage their members and leverage their resources, which is influenced by coalition processes, member participation and satisfaction and benefits outweighing costs. The current study used mixed methods, including coalition member surveys (n = 83) and semi-structured interviews with leaders and members (n = 42), to examine the process of creating collaborative synergy in 14 community coalitions for smoke-free environments in Armenia and Georgia. Members, typically seven per coalition representing education, public health, health care and municipal administration sectors, spent an average of 16 hr/month on coalition-related work. Common benefits included making the community a better place to live and learning more about tobacco control. The greatest cost was attending meetings or events at inconvenient times. Members contributed various resources, including their connections and influence, skills and expertise and access to population groups and settings. Strong coalition processes, greater benefits and fewer costs of participation and satisfaction were correlated with leveraging of member resources, which in turn, was highly correlated with collaborative synergy. Consistent with CCAT, effective coalition processes created a positive climate where membership benefits outweighed costs, and members contributed their resources in a way that created collaborative synergy.