Here we leverage the crystalline and tuneable family of (diamine)-M 2 (dobpdc) adsorbents to perform a systematic computational exploration of solid-state NMR parameters for different CO 2 adsorption products. We show that O solid-state NMR spectroscopy is a powerful new probe of CO 2 capture chemistry, providing unambiguous identification of carbamic acid formation and a detailed picture of the hydrogen-bonding environments.