Cretaceous volcanic rocks in the Sanandaj-Sirjan Zone (SSZ) preserve key evidence of tectonomagmatic processes associated with the subduction of the Neotethys Ocean. This research presents a comprehensive investigation of the petrography, whole-rock geochemistry, and petrogenesis of the volcanic rocks from the Qachian-Kani-Molla area (NW of Divandareh) to determine their origin, evolutionary processes, and tectonic setting. The studied rocks include basalt, basaltic andesite, and andesite, characterized predominantly by porphyritic and amygdaloidal textures, with plagioclase and clinopyroxene as the essential mineral phases. Geochemically, these rocks exhibit a sub-alkaline nature and belong to the medium- to high-K calc-alkaline series. Trace element patterns display characteristic features of volcanic arc magmatism, including enrichment in Large-Ion Lithophile Elements (LILE) such as K, Rb, and Th, and profound depletion in High-Field-Strength Elements (HFSE), particularly marked by negative Nb, Ta, and Ti anomalies. Tectonic discrimination diagrams consistently confirm an active continental arc setting for these rocks. Petrogenetic modeling indicates that the parental magmas were derived from low-degree (10–16%) partial melting of a garnet lherzolite mantle source, which had been metasomatized by subduction-derived fluids, at depths of approximately 100–110 km. The magmatic evolution from basaltic to andesitic compositions was primarily controlled by fractional crystallization of minerals such as plagioclase and clinopyroxene, coupled with crustal assimilation during magma ascent. The results of this study provide a precise petrogenetic model for one of the Cretaceous volcanic centers in the Sanandaj-Sirjan Zone and reinforce the active continental margin model for this tectonic domain.