Over fifteen years of concerted efforts of various institutions and individuals from Bangladesh, China, India, Myanmar since 1999 have finally moved the BCIM Forum from Track 2 to Track 1 level. BCIM-Economic Corridor proposal mentioned in two Joint Statements of prime ministers of China and India during 2013 and 2014 symbolises this upgradation by launching their first formal step forward concretising this sub-regional cooperation. While this format has enormous potential of reviving the physical connectivity (rail, road, aviation, navigation, energy pipelines) as also socio-cultural connections of minority communities that inhibit these remote regions of China's Southwest, India's northeast, northern Myanmar and Bangladesh, the key lies in their expanding interdependence facilitating not just their prosperity but also addressing their persistent unrest and violence with implications for national and regional security for these four nations. But the challenge lies in changing mindsets inherited from their colonial and cold war legacies that continue to make them susceptible to mutual distrust making them resistant and renitent towards such out of box propositions. Authors here seek to understand its evolution as also examine various challenges and opportunities in undertaking construction of this BCIM-Economic Corridor and explore multiple triggers and future trajectories of this sub-regional cooperation. Dr. Swaran Singh is Professor for Diplomacy and Disarmament at Jawaharlal Nehru University, New Delhi. He is president of Association of Asia Scholars, general secretary of Indian Congress of Asian and Pacific Studies and Guest Professor at Research Institute of Indian Ocean Economies, Yunnan University of Economics and Finance, Kunming, Yunnan, China. Dr. Zhu Cuiping is a Deputy Director of Research Institute for Indian Ocean Economies(RIIO), Yunnan University of Finance and Economics(YUFE), Kunming, China.