The Bathani volcano-sedimentary sequence (BVSs) is a typical example of volcanic-plutonic complex from the Proterozoic Chotanagpur Granite Gneiss Complex. We conducted petrological and geochemical studies on two domains of the BVSs; one is a granite pluton, while the other is a subvolcanic rhyolite dome. These two domains were intruded by mafic magmas during their evolution leading to magma mixing. The mafic rocks show tholeiitic trend, while calcalkaline affinities are displayed by the felsic rocks. The rocks display enriched LILE and fractionated REE patterns with enrichments in LREE relative to HREE. The felsic rocks have comparable whole-rock Sr-Nd isotopic compositions (( 87 Sr/ 86 Sr) = 0.7960-0.8596; ε Nd = -26.06 to -13.57), which are different from the Sr-Nd compositions of the mafic rocks (( 87 Sr/ 86 Sr) = 0.7036-0.7169; ε Nd = -7.07 to -1.99). The hybrid rocks show intermediate Sr-Nd compositions between mafic and felsic rocks (( 87 Sr/ 86 Sr) = 0.7116-0.8064; ε Nd = -23.76 to -4.56), which conform their mixed nature. Our results suggest that the BVSs evolved in an island arc subduction-related setting. Subduction of the South Indian Block beneath the North Indian Block during the Proterozoic led to the generation of mafic magmas in the mantle, which interacted with shallow crustal felsic magma chambers leading to magma mixing.