<p>The temporal structural evolution of nitrogen–water condensates under high vacuum and cryogenic conditions was investigated using temperature-resolved infrared spectroscopy and synchrotron X-ray diffraction. The premixed co-deposited mixture undergoes spontaneous segregation into distinct molecular phases, followed by transformation pathways analogous to those of the individual constituents. Promoted by the phase transitions of amorphous ice, structure II nitrogen hydrate emerges and coexists with hexagonal ice at elevated temperatures. Notably, a significant fraction of nitrogen remains retained within the ice matrix well above its nominal sublimation temperature. These findings demonstrate that hydrophobic species can be efficiently retained within amorphous ice at cryogenic temperatures under non-equilibrium conditions beyond their nominal sublimation regime.</p> Graphical abstract <p></p>