Carbon dioxide capture and storage is essential to reducing greenhouse gas emissions and meeting net-zero emissions targets. A range of technologies are under development to meet the need for more energy efficient carbon capture. One promising strategy to improve on traditional aqueous amine technology is to use solid adsorbent materials for capture. In particular, installation of reactive amine or hydroxide functional groups within a porous scaffold such as a metal-organic framework or a porous silica brings about selective reactivity with CO 2 , with the porous scaffold providing a large surface area for hosting the reactive groups while maintaining channels for CO 2 transport. The increasingly complex adsorbent materials under consideration bring major challenges in the characterisation of new carbon capture chemistry, hindering the design of improved materials. Existing characterisation tools for understanding CO 2 capture modes include single-crystal diffraction, powder diffraction, infra-red spectroscopy, X-ray absorption spectroscopy, and NMR spectroscopy, each of which has strengths and limitations in terms of the materials that can be studied and the information that can be obtained. Solid-state NMR spectroscopy is a promising tool for investigating CO 2 binding modes in adsorbents as there is no requirement for long-range ordering and detailed information about the local structure and dynamics of the CO 2 can be obtained. However, different CO 2 adsorption products often give rise to very similar signals in the NMR spectrum and assigning these signals to specific CO 2 binding modes remains very challenging. The most common experiment with the NMR approach is to dose the candidate adsorbent with CO 2 gas and perform C magic angle spinning (MAS) NMR experiments. These experiments are relatively straightforward to perform, but often lead to ambiguous identification of the adsorption products. For amine-functionalised materials, the C chemical shifts give poor differentiation between closely related ammonium carbamate, carbamic acid, and ammonium bicarbonate adsorption products, with the signals from these species showing very similar C chemical shifts. A similar problem arises for bicarbonate and carbonate products in hydroxide-based materials. The prediction of NMR parameters with densityfunctional theory (DFT) calculations can improve confidence in the structural assignments, and more advanced multi-nuclear NMR experiments can give improved differentiation between adsorption products. However, there remains a pressing need for the exploration of new NMR methods for understanding CO 2 capture chemistry. A representative emerging class of CO 2 adsorbents are amine-functionalised metal-organic frameworks. The framework M 2 (dobpdc) (dobpdc = 4,4'-dioxidobiphenyl-3,3'-dicarboxylate) (Figure ) can straightforwardly be functionalised with amines to yield a family of (amine)-M 2 (dobpdc) adsorbents (Figure ). These adsorbents have large capacities for selective and reversible CO 2 uptake, and the adsorption thermodynamics can be tuned by varying the amine, and the metal. Importantly, these materials generally display steep adsorption isotherms making them promising for a range of energy efficient carbon capture applications. Initial characterisation of CO 2 adsorption modes in these materials has revealed a rich chemistry, with three CO 2 adsorption products proposed to date: (i) ammonium carbamate chains (Figure ), thought to be the dominant product in a range of variants, (ii) carbamic acid pairs (Figure ), identified in the Zn-based framework functionalised with the diamine dmpn (dmpn = 2,2-dimethyl-1,3-diaminopropane), and (iii) a mixed adsorption product (Figure ) recently proposed for (dmpn)-Mg 2 (dobpdc). The adsorption thermodynamics of these three adsorption processes vary, motivating further characterisation to aid the design of metal-organic frameworks with the best CO 2 capture performances.