Participatory action research (PAR) is both a research methodology and nonhierarchical form of knowledge production that brings together participants from both academia and outside communities in a collaborative research partnership that seeks social transformation. Research on PAR consistently mentions collaboration, the naming of power dynamics, and dialogue as central to the inquiry process (McTaggart, 1989, 1991; Genat, 2009; Cahill, 2016; Fox & Fine, 2016). Yet research is sparse on how the collaborative relationship develops and is sustained over time. This qualitative and ethnographic study (Denzin & Lincoln, 2005; Harrison 2018) explored the collaborative relationship that occurs in PAR, through an interdisciplinary undergraduate research at the University of Puerto Rico-Cayey. The course integrated an intersectional social justice curriculum exploring race, class, gender, sexuality, ability, and colonialism relevant to Puerto Rico's context; the planning, development, and implementation of various PAR projects; and the incorporation of practices used by a critical dialogic methodology called intergroup dialogue (IGD). IGD brings together people from different social identity groups to explore social justice issues and develop mutual understanding and alliances across differences (Zúñiga, Nagda, & Zevig, 2002). Drawing from 34 interviews with students and community partners, document analysis, participant observation, and autoethnographic memos, the study examines the collaborative process and meaning making co-created throughout the experience by the students, community partners, and faculty member engaged in PAR. The PAR projects and the study are guided by the work of Black, Indigenous, and women of color feminists. This body of antiracist feminist and decolonial scholarship situates solidarity as a relational, political, and ethical practice, calling attention to the ways difference can be mobilized in the struggle for decolonization, without flattening or erasing differences. Findings suggest that the PAR team created a methodology of solidarity by paying explicit attention to the collaborative process, engaging in dialogue to discuss oppression, colonialism, and its manifestations in our everyday lives, and working interdependently to co- create a community collective that went beyond the course. This study also shows how merging of IGD and PAR fosters the building of trust, reciprocity, mutual responsibility, and ultimately, solidarity across differences in the collaborative relationship.