This applied–developmental research, conducted as a cross-sectional survey study, aimed to design a strategic development model for Iran–China digital diplomacy using a multi-grounded theory approach. The analysis stage began with meta-synthesis to extract and integrate concepts, after which the findings were processed through the multi-source grounded theory approach using open, axial, and selective coding with the MAXQDA software. According to the extracted paradigm model, digital transformation in international governance, competition among cyber powers, and the shift in soft-power and public-diplomacy patterns—together with technological cooperation within the Eastern bloc—serve as causal conditions influencing the formation of the core phenomenon (Iran–China digital diplomacy). This phenomenon evolves in interaction with a shared technological ecosystem, communication infrastructures, institutional alignment, and agile digital policies as contextual conditions, as well as geopolitical challenges, cyber-security concerns, and cultural-cognitive barriers as intervening conditions. These dynamics ultimately shape strategic actions such as joint technological investment, co-development of digital technologies, and shared governance of strategic technologies. Implementing these strategies leads to outcomes including enhanced performance, strengthened digital soft power, the advancement of data-driven governance, and the institutionalization of technological cooperation within the framework of Eastern convergence.