Metal-exchanged zeolites have been widely used in industrial catalysis and separation, but fundamental understanding of their structure-property relationships has remained challenging, largely due to the lack of quantitative information concerning the atomic structures and reaction-relevant adsorption properties of the embedded metal active sites. We report on the use of low-temperature chemisorption to titrate Cu-exchanged ZSM5. Quantitative descriptors of the atomic structures and adsorption properties of Cu-ZSM5 are established by combining atomistic simulation, DFT calculations, operando molecular spectroscopy, chemisorption and titration measurements. These descriptors are then applied to interpret the catalytic performance of Cu-ZSM5 for NO decomposition. Linear correlations are established to bridge the low-temperature adsorption analytics and high-temperature reaction kinetics, which are demonstrated to be generally applicable for understanding the structure-property relationships of metal exchanged zeolites and foregrounded for guiding the development of advanced catalytic materials.