This work reports the green synthesis of the Cu/reduced graphene oxide/Fe3O4 (Cu/RGO/Fe3O4) nanocomposite as a new catalytic system for cyanation of aldehydes to nitriles. This nanocomposite catalytic system was synthesized by aqueous extract of leaves of Euphorbia bungei Boiss as a reducing and stabilizing agent. Various substituted aryl nitrile were prepared under optimized conditions and providing moderate to excellent yields. In this process the catalyst exhibited a strong magnet response and could be easily separated by an external magnet and reused with no loss of catalytic activity. (C) 2016 Elsevier Inc. All rights reserved.