Solution equilibria and relevant stability constants for M(II)-pyridoxine (PN)(A) [M(II) = Cu(II), Ni(II), and Zn(II)], and M(II)-PN(A)-imidazole containing ligands (B) [B = imidazole (him), benzimidazole (bim), histamine (hist), and L-histidine (his)] in aqueous solution have been determined by a pH metric method at 310 K and I = 0.15 M NaClO4. The complexation model for each system has been established by the MINIQUAD-75 program. The probable binding mode in the binary and ternary species was discussed based upon the derived stability constants. The concentration distributions of various species formed in solution were evaluated. The stability of ternary complexes follows the Irving-Williams order of metal ions, which was quantitatively (Delta log K, log X, and % RS) compared with their corresponding binary complexes. In terms of the ligands (B), the stability of the complexes follows him > bim > hist > his. The molecular geometry of the complexes formed in solution between the ligands and M(II) was determined by electronic spectra at various pH intervals. The formation of complexes and their electrochemical properties were also assessed by cyclic voltammetry. The in vitro biological activity of the ternary complexes was tested against bacteria, fungi, and yeast.