Figure S1-1. ¹H NMR spectrum of m-BPMC.

Figure S1-2 ¹⁹F NMR spectrum of m-BPMC.

Figure S1-3 ESI-HRMS spectrum of m-BPMC.

Figure S2-1 ¹H NMR spectrum of o-BPMC.

Figure S2-2 ¹⁹F NMR spectrum of o-BPMC.

Figure S2-3 ESI-HRMS spectrum of o-BPMC.

Figure S3-1 ¹H NMR spectrum of m-BPHC.

Figure S3-2 ¹⁹F NMR spectrum of m-BPHC.

Figure S3-3 ESI-HRMS spectrum of m-BPHC.

Figure S4-1 ¹H NMR spectrum of o-BPHC.

Figure S4-2 ¹⁹F NMR spectrum of o-BPHC.

Figure S4-3 ESI-HRMS spectrum of o-BPHC.

Figure S5-1 ¹H NMR spectrum of complex 1

Figure S5-2 ¹⁹F NMR spectrum of complex 1

Figure S5-3 ³¹P NMR spectrum of complex 1

Figure S5-4 ESI-HRMS spectrum of complex 1

Figure S6-1 ¹H NMR spectrum of complex 2

Figure S6-2 ¹⁹F NMR spectrum of complex 2

Figure S6-3 ³¹P NMR spectrum of complex 2

Figure S6-4 ESI-HRMS spectrum of complex 2

Figure S7-1 ¹H NMR spectrum of complex 3

Figure S7-2 ¹⁹F NMR spectrum of complex 3

Figure S7-3 ³¹P NMR spectrum of complex 3

Figure S7-4 ESI-HRMS spectrum of complex 3

Figure S8-1 ¹H NMR spectrum of complex 4

Figure S8-2 ¹⁹F NMR spectrum of complex 4

Figure S8-3 ³¹P NMR spectrum of complex 4

Figure S8-4 ESI-HRMS spectrum of complex 4

Figure S9 UV-Vis spectra of m-BPMC and Co(m-BPMC)(1) (b) o-BPMC and Co(o-BPMC)(2) (c) m-BPHC and Co(m-BPHC)(3) (d) o-BPHC and Co(o-BPHC)(4) in the dichloromethane.

Figure S10 XPS survey scan of a) corrole 2, b) corrole 3, c) corrole 4

Figure S11 The redox couple of ferrocene in DMF containing 0.1 M TBAP with blank glassy carbon as the working electrode.

Figure S12 CVs of 0.8 mM (a)1, (b)2, (c)3 and (d)4 with a varying scan rate (v) from 100 mV/s to 400 mV/s using the glassy carbon as the working electrode and plots of the maximum current (ip) for the reduction and oxidation waves vs. the scan rate (v1/2).

Figure S13 CVs of 0.8 mM (a) m-BPMC, (b) o-BPMC, (c) m-BPHC and (d)m-BPHC in 0.1 M TBAP/DMF.

Figure S14 CVs of Co(OAc)2 • 4H₂O (0.8 mM) and a mixture of freebase corroles,

Co(OAc)₂ • 4H₂O and PPh₃ in DMF

Figure S15 CVs of different equivalent acids (a) AcOH, (b) TFA in absence of catalyst.

Figure S16 i_cat /i_p plots of corrole complex 1–4 in AcOH.

Figure S17 i_cat /i_p plots of corrole complex 1–4 in TFA.

Figure S18 The Tafel plots of 0.8 mM corrole 1–4 in the presence of 16 equiv. AcOH.

Figure S19 The Tafel plots of 0.8 mM corrole 1–4 in the presence of 32 equiv. TFA.

Figure S20 CVs of 0.35 μM complexes 1–4 in aqueous medium.

Figure S21 Charge increase in absence of catalyst at different overpotentials.

Figure S22 Charge increase of 3.5 μM a) complex 2, b) complex 3, c) complex 4 at different overpotentials.

Figure S23 Charge increase of complex 1–4 at −1.45 V vs Ag/Ag/Cl.

Figure S24 Charge increase in absence of catalyst at −1.45 V vs Ag/Ag/Cl

Figure S25 GC spectrum of blank buffer solution after 1 h CPE at −1.45 V vs Ag/AgCl with 0.5 ml CH₄ as contrast.

Figure S26 CPE of 1, 2, 3, and 4 in 0.25 M pH = 7 phosphate buffers at −1.45 V vs NHE using GC as the working electrode.

Figure S27 UV-vis spectra of complexes 1–4 before and after electrolysis at −1.45 V vs Ag/AgCl for 6 h.

Table S1. Crystal data of complex 2.

Table S2. The selected bond distances (Å) for complex 2.

Table S3. The selected Bond Angles (°) for complex 2.

Table S4 The comparison of TOFs of cobalt complexes measured in neutral buffer or acidic system for HER.