Many analytical techniques for determination of Mn2+ are costly and required pre-sample treatment of analyte and even required very skilled person as supervisor to handle the instrument. Beside this the technique, ion-selective electrode is simple, easy to handle and very cheap to design. The present research describe the use of N1,N4-bis(salicylidene)-S-methylisothiosemicarbazidium chloride methanol monosolvate (H2L∙HCl∙CH3OH) (figure) as ionophore in PVC-based sensor for the determination of Mn2+. The synthesis of the ligand has been realized by demetallation of the NiL2 described in [1]. The structure of the H2L∙HCl∙CH3OH was determinate by single crystal X-ray diffraction.figureFigure: The structure of N1,N4-bis(salicylidene)-S-methylisothiosemicarbazidium chloride methanol monosolvate A polymeric membrane based on H2L∙HCl∙CH3OH has been prepared. Using this membrane has been confectioned electrochemical sensor for Mn2+. The parameters of the electrode have been established during their calibration in different manganese(II) concentration solutions. Ion-selective electrode exhibited a linear Nernstian response over the range 1*10-4-1*10-1 M with slope of 26 - 27 mV per decade. It shows a fast response time (20 - 60 s). The potentiometric selectivity coefficients were determined by separate interferent method. Their values show that sensor is substantially selective for Mn2+ ions over the all interfering ions studied. It was studied the influence of the anion nature of the response of sensor. Best results were recorded when calibration solutions were prepared using manganese(II) sulfate.