The transfer of Imam al-Riḍā (as) to Marv following his appointment as heir apparent placed him at the heart of a diverse multicultural environment. Within this historical context, and by the initiative of al-Ma’mun’s court, organized debate sessions were regularly convened between prominent representatives of various religions and theologians of diverse sects. The primary objective of this research is to identify the specific operational model and argumentative methodology underlying the Imam’s engagement with this religious diversity. While previous studies have often evaluated these sessions merely from a traditional theological perspective, the present article, utilizing a historical-analytical method based on a comparative reading of historical texts, focuses specifically on the structure and systematic logic of these dialogues. The primary research sources—specifically ʿUyūn Akhbār al-Riḍā, al-Tawḥīd, and al-Iḥtijāj—have been utilized with critical source-based scrutiny. The research findings indicate that these debates were grounded in a coherent operational model of “Jadal-e Ahsan” (better argumentation), the central feature of which is a “methodological gradation from Revelation to Reason.” This model consists of three fundamental components: rational reasoning coupled with a complete avoidance of takfir; compelling the interlocutor through their own sacred texts and accepted epistemological foundations; and maintaining the dignity of the opposing party throughout the debate. A comparative analysis of five landmark debates—with the Catholicos, the Exilarch, the Hirbadh, Imran al-Sabi, and Sulayman al-Marwazi—demonstrates the consistency, coherence, and dynamism of this operational model across vastly different situations. In this process, the Imam began the discourse from a point of textual commonality and, to avoid textual stalemates, elegantly elevated the level of the debate to pure rational proofs. Consequently, this article reconstructs the Riḍawi debates as a systematic historical model for interreligious dialogue.