Two zinc(II) complexes, [(ZnLBr)-Br-1](+) (1), and [ZnL2](2+) (2), are optimized by using density functional theory at B3LYP method with mix basis sets which are LANL2DZ/6-31G(d,p) and LANL2TZ+/6-31++G(d,p) basis sets. L-1 and L-2 are pentadentate macrocyclic Schiff-base ligands containing piperazine moiety. The optimized structures and structural parameters are obtained by using each basis set. IR and UV-VIS spectra of complex (1) and (2) are investigated in detail. NLO properties of Zn(II) complexes are investigated and it is found that NLO properties of complex (2) is better than complex (1). Solvent effects on biological activity are investigated in gas phase, water and chloroform for studied complexes and no solvent effects are monitored for complex (1) and (2). Biological reactivity of complex (1) is higher than that of complex (2).