Indigo blue was discovered as a semiconductor material because of its organic semiconductor properties. This paper shows a primary study of the electrochemical properties of Sakon Nakhon-indigo strain used in the metal–semiconductor–metal (MSM) diode. The fermentation and extraction of our local indigo plant are explained. Indian indigo in the MSM diode is compared in the same conditions of preparation. The electrochemical properties, including the current–voltage (I–V) characteristic, static resistance, and rectification ratio, are discussed. The results show that the electron and hole characteristics and band gap energy of the indigo blue affects the electrochemical properties of the device. Our local MSM diode has a suitable operation between −1 and +3 VMSM with a knee voltage of 1.0 VMSM. Especially, it can produce the highest forward-bias current of about 3.19 mA at linear operation between +2 and +3 VMSM, whereas the review MSM diode is about 2–3 hundred times lower. This shows that this strain has more conductive properties because of its effective electron and hole characteristics obtained by an indigo yield concentration. Therefore, the MSM diode based on Sakon Nakhon-indigo strain is an important role in an electronic semiconductor device for low voltage consumption and high sensitivity. In the future, the molecular characteristics of local indigo may be deeply analyzed to be further developed into a thin-film form used as an organic semiconductor material in several electronic devices.