The paper focuses on the issues of transforming the geographically spread co-working spaces of start-up firms into the open knowledge ecosystems, i.e. hubs of growth-focused organizations characterised by sharing and generating new industrial knowledge. The presented insights are based on the combination of theoretical review and empirical survey of 92 managers of start-ups and SMEs in Lithuania. This is an emergent community of regional start-up firms with rudimentary linkages and elements of knowledge sharing. The paper looks into the key issues that could contribute to strengthening the knowledge-based collaborations and synergies in such community, while assessing both the current situation and the evolutionary potential of such collaborations. We present the critical discussion in the light of ecosystem-as-structure vs. ecosystem-as-affiliation (Adner, 2017) approaches. Ecosystem-as-affiliation approach stresses the affiliation of ecosystem actors (to the network or focal actor), while ecosystem-as-structure views ecosystem through the lense of value proposition that network actors are co-creating. The first view has a more open-ended network perspective where spontaneous collaborations may lead to different outcomes and the network welcome different members with no prior objective in sight. The second view is more focused on aligning the resources and activities of multilateral set of partners for materialising specific value propositions, and members are invited to join based on these specific needs. The research has shown that, on one hand, the emergent start-up community relies on institutional coordination while retaining the element of openness. On the other hand, there is an explicit need for leadership in building the shared vision and designing the knowledge partnerships for delivering the shared value propositions. One should stress the importance of focal organizations and boundary spanners - both in terms of the organizational and knowledge boundaries. The shared business interests, network leadership and trust have been identified as the key cornerstones for further development of network into an open knowledge ecosystem, yet they are also associated with the greatest challenges to sustained knowledge sharing in the network.