AbstractThe formation, and subsequent structural, thermal and adsorptive properties of single‐component metal–organic framework crystal‐glass composites (MOF‐CGCs) are investigated. A series of novel materials exhibiting chemically identical glassy and crystalline phases within the same material were produced, where crystalline ZIF‐62(Zn) was incorporated within an a_gZIF‐62(Zn) matrix. X‐ray diffraction showed that the crystalline phase was still present after heating to above the glass transition temperature of a_gZIF‐62(Zn), and interfacial compatibility between the crystalline and glassy phases was investigated using a mixed‐metal (ZIF‐62(Co))_0.5(a_gZIF‐62(Zn))_0.5 analogue. CO₂ gas adsorption measurements showed that the CO₂ uptakes of the MOF‐CGCs were between those of the crystalline and glassy phases.