Images of possible, probable and preferred futures shape organisational action in the present. This paper explores how utopian and dystopian imaginaries shape collective identities in nascent entrepreneurial fields. We focus on the emerging entrepreneurial field of ‘blockchain for good’ as a site to explore how utopian and dystopian imaginaries shape collective identity. We adopt a methodology from futures studies, Textor’s ethnographic futures, to elicit utopian and dystopian imaginaries through interviews with 40 blockchain entrepreneurs developing alternative approaches to decentralised finance. Our findings reveal how their utopian and dystopian imaginaries exist in a dialectical relationship, shaping and being shaped by each other to create utopian dystopias and dystopian utopias. We show how this utopia-dystopia dialectic triggers mechanisms of 'othering', 'claiming and reclaiming utopias', and 'sensing co-opted utopias' which influences collective identities as entrepreneurs establish coalitions of 'good actors' and distance themselves from those perceived as leading towards dystopian futures. Our study contributes to the literature on future imaginaries and collective identity in nascent entrepreneurial fields by showing how the dialectical relationship between utopian and dystopian imaginaries shapes collective identity formation. Further, we extend our understanding of the role of othering in creating shared utopias and shaping collective identities in emerging fields by creating coalitions of ‘good’ actors and spaces for critique of those leading a path towards another dystopia.