Throughout the history of Iranian Islamic architecture, inscriptions have played a significant role not only as carriers of religious, historical, and cultural messages but also as important decorative elements that contribute to the aesthetic and spatial qualities of architectural monuments. Among the various decorative techniques employed in Islamic architecture, stucco decoration achieved a particularly distinguished status due to its flexibility, durability, and capacity to accommodate both calligraphic and ornamental compositions. During the Ilkhanid period, the art of stucco reached a remarkable level of technical and artistic sophistication. Artists and craftsmen of this era demonstrated exceptional mastery in integrating architectural space with decorative elements, creating harmonious compositions in which script and ornamentation functioned as complementary visual components. As a result, Ilkhanid stucco inscriptions represent some of the finest examples of artistic innovation and aesthetic refinement in the history of Iranian Islamic art. Among the most important surviving examples of Ilkhanid stucco decoration are the mihrab and inscriptions of the Kermani Mosque, located within the architectural and funerary complex of the tomb of Sheikh Ahmad Jam in Torbat-e Jam, northeastern Iran. This complex is recognized as one of the most valuable religious and historical monuments of the Islamic period and contains numerous decorative features that reflect the artistic achievements of the Ilkhanid era. The stucco inscriptions of the mosque are particularly noteworthy because of their intricate combination of Qur’anic texts and vegetal ornamentation. These inscriptions not only convey sacred meanings through written words but also demonstrate a sophisticated visual relationship between script and decorative motifs. The present study aimed to investigate and compare the manner in which Script and ornament coexist within two significant stucco inscriptions of the Kermani Mosque: the inscription containing verses from Surah Fath and the inscription containing parts of Surah Yasin. The research sought to identify the structural and visual relationship between script and ornament in these inscriptions and to determine how decorative motifs contribute to the overall composition while maintaining the primacy of the Qur’anic text. More specifically, the study attempted to answer the following question: What type of relationship exists between Script and ornamental motifs in the inscriptions of Surah Fath and Surah Yasin, and how do these elements interact to create a unified artistic composition? This research was conducted as a fundamental qualitative study employing a descriptive-analytical method with a comparative approach. The investigation relied on both theoretical and empirical sources of information. Data were collected through documentary studies, library resources, and direct field observations of the inscriptions. The statistical population of the research consisted of the inscription of Surah Fath and a selected section of the inscription of Surah Yasin located in the Kermani Mosque. Detailed visual analysis was carried out to examine the formal characteristics of the inscriptions, including the arrangement of letters, the organization of decorative motifs, the use of positive and negative space, and the hierarchical relationship among the various decorative layers. The comparative analysis revealed that both inscriptions share a common compositional system in which script and ornamentation are carefully coordinated to achieve visual harmony and structural coherence. Although the inscriptions differ in certain details of execution and decorative treatment, they are based on a similar artistic principle that places the script at the center of the composition. The study found that the integration of script and motif is organized through a multi-layered structure consisting of three distinct levels of depth and elevation. In the first and most prominent layer, the calligraphic inscription serves as the principal element of the composition. The script occupies a dominant position and functions as the primary organizing framework upon which all other decorative components depend. Beyond its textual and religious significance, the script establishes the rhythm, proportions, and spatial organization of the entire inscription. The forms of the letters create a visual structure that guides the placement and distribution of subsequent ornamental elements. The second layer consists of Eslimi motifs and geometric motifs that are inserted into the negative spaces generated by the arrangement of the script. These motifs are not randomly distributed; rather, they are carefully adapted to the spaces defined by the calligraphic forms. Their purpose is both decorative and compositional, as they contribute to visual balance while enhancing the aesthetic richness of the inscription. The interaction between script and motif at this level demonstrates the artist’s ability to transform empty spaces into active visual components without compromising the legibility or dominance of the text. The third layer is composed primarily of Khataai motifs, which fill the remaining vacant areas and complete the decorative composition. These motifs function as supplementary elements that enrich the surface and create a sense of continuity throughout the inscription. Their placement is determined by the spatial conditions established by the first and second layers, indicating a hierarchical relationship among all decorative components. In other words, the execution of both the second and third layers is fundamentally influenced by the arrangement and structure of the calligraphic layer. The findings of this study demonstrate that the relationship between script and motif in the stucco inscriptions of the Kermani Mosque is neither independent nor merely decorative. Instead, it is based on a carefully planned hierarchical system in which script acts as the governing element and ornamentation responds to the spatial and formal requirements established by the script. This approach reflects the aesthetic principles of Ilkhanid art, where textual content, visual beauty, and architectural function are integrated into a unified artistic whole. The inscriptions of Surah Fath and Surah Yasin therefore provide valuable evidence of the sophisticated methods employed by Ilkhanid artists in combining sacred text with ornamental design, illustrating the high level of creativity and technical expertise achieved in the stucco decoration of Iranian Islamic architecture.