An immobilized copper (II) complex on micro cellulose (Cell-DABCO-Cu) was synthesized and characterized by FT-IR, TGA and SEM. The catalytic activity of Cell-DABCO-Cu was evaluated as a recoverable and green catalyst for four-component synthesis of 2H-indazolo[1,2-b]phthalazine trione derivatives in solvent free condition. The notable advantages of this procedure include excellent yields, short experimental time, and easy preparation of the catalyst. The feature of this work is using of Cell-DABCO-Cu as a starting material to prepare single phase CuO nanoparticles (CuO NPs) via a solid-state decomposition procedure. The CuO nanoparticles with average size of 40 nm were obtained by the direct calcination of Cell-DABCO-Cu.