A simple spectrophotometric method has been developed for the determination of Nickel (II) by using Schiff base 2- [(2-hydroxyphenylimino) methyl]-4-nitrophenol [HPIMNP]. HPIMNP extracts Ni (II) quantitatively (99.92%) into n-Butyl alcohol from an aqueous solution of pH range 7.8 - 8.8 in the presence of 2 ml of 5 M solution of Ammonium chloride. The n- Butyl alcohol extract shows maximum absorption at 480 nm (λ max). Beer’s law is obeyed over the Ni (II) concentration range 0.2-20.0 μg/ml. The molar absorptivity and sandell’s sensitivity of Nickel- HPIMNP system is 882.35 L mole-1 cm-1 and 0.067 μg.cm-2 respectively. The composition of extracted species is found to be 1:2 (Ni: HPIMNP) by Job’s continuous variation and Mole ratio method. Interference by various ions has been studied. The proposed method had been applied for determination of Ni (II) in alloy samples.