5-phenylazo-8-hydroxyquinoline and its newly metal complexes with Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) metal ions have been prepared and characterized using different analytical techniques. The complexes are distorted octahedral binding via one oxygen and nitrogen atoms of the ligand; two/three coordinated water molecules. 1:1 complexes contain one chloride or OH − ion and some complexes have one or two water of hydration whereas 1:2 complexes contain only two coordinated water molecules in their coordination spheres. All complexes behave as neutral in dimethylformamide (DMF). The electronic structure and non-linear optical parameters NLO of the complexes (ML and ML2) are investigated theoretically at the B3LYP/GEN level of theory. The geometries of the studied complexes are non-planner. The calculated E HOMO and E LUMO energies of the studied complexes were used to calculate the global properties; hardness (η), global softness (S) and electronegativity (χ). The total dipole moment (μ tot ), static total and anisotropy of polarizability (α, Δα) and static first hyperpolarizability (β) values were calculated and compared with urea as a reference compound. The studied complexes show promising optical properties.