A versatile post-synthetic modification strategy to functionalize a high surface area microporous network (MPN-OH) by bioorthogonal inverse electron-demand Diels-Alder (IEDDA) ligation is presented. While the polymer matrix is modified with a readily accessible norbornene isocyanate (Nb-NCO), a set of functional entities, presenting the robust asymmetric 1,2,4,5-tetrazine (Tz) allows easy functionalization of the MPN by chemoselective Nb/Tz ligation. A generic route is demonstrated, modulating the internal interfaces by introducing carboxylates, amides or amino acids as well as an oligopeptide d-Pro-Pro-Glu organocatalyst. The MPN-Peptide construct largely retains the catalytic activity and selectivity in an enantioselective enamine catalysis, proving remarkable availability in different solvents, offers heterogeneous organocatalysis in bulk and shows stability in recycling settings.