New peripherally (β) and non-peripherally (α) substituted metal octakis(hexylthio)phthalocyanines (β- and α-MOcHexTPc) containing cobalt and manganese as metal centers were synthesized. Their characterization using electrochemical methods showed that these complexes exhibit several redox processes at E_1/2 (mV vs. Ag∣AgCl) = 380 (212) (I), 1140 (864) (II), -450 (-460) (III) and -1170 (-1304) (IV) for β- (α-) CoOcHexTPc . These redox processes were assigned to Co^IIIPc^-2/Co^IIPc^-2 (I) , Co^IIIPc^-1/Co^IIIPc^-2 (II) , Co^IIPc^-2/Co^IPc^-2 (III) and Co^IPc^-2/Co^IPc^-3 (IV) using spectroelectrochemistry. For the β- (α-) MnOcHexTPc complex the redox processes were observed at E_1/2 (mV vs. Ag∣AgCl) = -20 (5) (I), -530 (-640) (II) and -1270 (-1380) (III) and were assigned to Mn^IIIPc^-2/Mn^IIPc^-2 (I), Mn^IIPc^-2/Mn^IIPc^-3 (II) and Mn^IIPc^-3/Mn^IIPc^-4 (III) . Electrochemical and microscopic characterization using AFM showed that the self-assembled monolayers (SAMs) are formed on the gold surface using these complexes. The electrochemical characterization showed the blocking of the Faradaic processes at SAMs modified electrodes and these reactions are well-known to easily occur at unmodified gold electrodes. The AFM characterization showed an increase in surface roughness upon modifying the gold surface with MOcHexTPc SAMs, further confirming the presence of the monolayers on the gold surface. The MOcHexTPc SAMs were investigated for their electrocatalytic application towards H₂O₂ detection. The MOcHexTPc SAMs modified gold electrodes gave excellent currents for H₂O₂ detection. The observed H 2 O₂ electrocatalytic reduction peaks were close to where the metal redox processes from the MOcHexTPc occurred, showing the involvement of the metal redox processes in the electrocatalytic mediation reactions.