Emerging technologies and community empowerment have driven citizen science (CS) projects. However, their impact remains vague, partly because of the difficulties in monitoring and standardizing these projects. Notably, the development of citizens' complex thinking is not among the primary goals, despite the connection with the tenets of Education 4.0 and the training of socially committed citizens. Therefore, we propose a framework and typology to foster CS projects while scaling up complex thinking. We used the evidence-based educational innovation (EBEI) methodology and the Theory of Change (ToC) perspective, reviewing some of the most relevant frameworks under UNESCO's Open Science Recommendation. Findings from the CS projects analysis revealed that: (a) there is inattention to developing the sub-components of the complex thinking macro-competency; (b) a growing trend to develop frameworks for CS projects is taking place; (c) there is a prevalence of CS project frameworks focused on prevention and control, project evaluation and design, and education and research; (d) a framework with three dimensions based on ToC (Outbound, Threshold and Full-cycle) can guide the development of CS projects; and (e) an eight-component typology can measure the progress and impact of CS projects from the perspectives of Context-awareness, Citizen engagement, Infrastructure leverage, Technological innovation, Educational innovation, Outreach and Scale, Network building, and Complex Thinking. We envision that the integrated framework and typology proposed, scaffolded by complex thinking, can comprehensively broaden the impact of CS initiatives.