The conservation of crystal geometry for Cstars with widely different arm length offers a powerful route for the preparation of nanoporous materials with programmable porosity, which we characterize by determining the degree of penetration of various (macro)molecular probes within the crystals. We chose a variety of fluorescent probes to cover a broad range of molecular weight, hydrodynamic size, hydrophobicity, and chemical nature, including sodium fluorescein (FAM), fluorescein-modified dextrans (3kDa DXT-FAM, 10kDa DXT-FAM), rhodamine B, recombinant green fluorescent protein (rGFP), and fluorescently labelled streptavidin (SAv-A647). Crystals were soaked in solutions containing the (macro)molecules, and their penetration was determined by extracting the ratio ξ = I internal /I external between the fluorescence intensity measured inside and outside the crystals from confocal micrographs. Macromolecule partitioning is clearly dependant on l, as shown by Fig. , with all of the hydrophilic probes trialled, namely FAM, DXT FAM and rGFP, following the trend of longer arm length leading to increased penetration. As expected, larger molecular weight leads to lower penetration for a fixed l.