a novel acrylic acid-functionalized fe3o4 magnetic nanoparticle with a core-shell structure was developed for utilization as a heterogeneous organosuperacid in chemical transformations. the structural, surface, and magnetic characteristics of the nanosized catalyst were investigated by various techniques such as transmission electron microscopy (tem), thermogravimetric analysis (tga), and ft-ir. the acrylic acid-functionalized fe3o4 nanoparticles great potential for application in magnetically separation technologies. in application point of view, the prepared catalyst was found to act as an efficient recoverable nanocatalyst in bisindol and benzimidazole reactions in solvent-free media under mild condition. additionally, the catalyst was reused three times without significant degradation in catalytic activity and performance.