This study tries to deal with knowledge collaborative approach of relationship learning which is a strategic perspective entails of creating collective knowledge to demonstrate the role of inter-organizational learning through project-based organizations (PBOs). This helps in enhancing the abilities of non-governmental organizations (NGOs) in metropolitan areas witnessing duality in the legal framework under which these organizations operate, and how such circumstances affect NGOs operating in autonomous regions to maintain long-term linkages with their partners to achieve sustainable development. Based on a survey conducted from 146 respondents, we have illustrated that inter-organizational learning was significantly associated with building the capacity of NGOs to maintain long term linkages with international partners, as well as its significant relation-ship with obtaining sustainable performance. Moreover, the value creation has appeared to have a partial mediation role between inter-organizational learning and sustainable performance while legal framework seems to have a significant moderator role in hindering the relationship between interrelation learning and value creation.