Following characterisation of the samples, electrode films composed of Cu3(HHTP)2, acetylene black and PTFE in the ratio 85:10:5 were fabricated, as in previous studies. SEM imaging confirmed that the microstructures observed in powdered samples were broadly maintained following film formation (SI Fig. ). The energy storage performances of A-CuHHTP, B-CuHHTP, and C-CuHHTP were then investigated by assembling symmetric supercapacitor cells with both an organic electrolyte, 1 M NEt4BF4 in acetonitrile (ACN), and an ionic liquid electrolyte, EMIM-BF4. All cells with a given electrolyte were assembled with similar electrode mass loadings where possible to allow for fair comparison, and the contributions of both acetylene black and PTFE to the capacitive performance were removed (SI Table , Fig. ).