The spherical shaped Fe3O4-Cu nanocomposite was synthesized by a simple chemical reduction method by using L-arginine as a linker. The resultant Fe3O4-Cu nanocomposite was characterised and used for chemoselective reduction of 5-nitroisopthallic acid in the presence of sodium borohydride by UV-Visible spectrophotometric method. Fe3O4-Cu photocatalyst is cost-effective, easily recyclable, and do not affect environmental conditions. Also, we compared the catalysis study of Fe3O4 nanoparticles and Fe3O4-Cu nanocomposite for reduction of 5-nitroisopthallic acid. Fe3O4-Cu nanocomposite showed better catalytic activity than Fe3O4 nanoparticles. The unique properties of Fe3O4-Cu nanocomposite make an ideal platform for catalysis, sensing applications and in green chemistry. Keywords: Fe3O4-Cu, Photocatalyst, 5-Nitroisophthalic Acid, 5-Aminoisopthalic acid, Catalytic reduction.