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Space-based mid-IR spectroscopy provides tracers of warm gas in star-formingregions that are inaccessible from the ground. Past mid-IR spectra of brighthigh-mass protostars in the hot-core phase typically showed strong absorptionfeatures from molecules such as CO$_2$, C$_2$H$_2$, and HCN. However, little isknown about their fainter counterparts at earlier stages. We thus aim tocharacterize the gas-phase molecular features in JWST MIRI/MRS observations ofthe young high-mass star-forming region IRAS 23385+6053. Spectra were extractedfrom two mid-IR sources and three H$_2$ bright outflow knots in the MIRI/MRSfield of view. Rich molecular spectra with emission from CO, H$_2$, HD, H$_2$O,C$_2$H$_2$, HCN, CO$_2$, and OH are detected towards the two mid-IR sources.However, only CO and OH are seen towards the brightest H$_2$ knots, suggestingthat the majority of the observed species are associated with disks or hot coreregions rather than outflows. Simple Local thermodynamic equilibrium (LTE) slabmodels were used to fit the observed molecular features. The LTE model fits to$^{12}$CO$_{2}$, C$_{2}$H$_{2}$, and HCN emission suggest warm $120-200$ Kemission arising from a disk surface around one or both protostars. Weak$\sim500$ K H$_2$O emission at $\sim$ 6-7 $\mu$m is detected towards one mid-IRsource, whereas $250-1050$ K H$_2$O absorption is found in the other. TheH$_2$O absorption may occur in the disk atmosphere due to strongaccretion-heating of the midplane, or in a disk wind viewed at an ideal anglefor absorption. CO emission may originate in the hot inner disk or outflowshocks. OH emission is likely excited in a non-LTE manner through waterphotodissociation or chemical formation. The observations are consistent withdisks having already formed in the young IRAS 23385+6053 system, but furtherobservations are needed to disentangle the effects of geometry and evolution.

JOYS: MIRI/MRS spectroscopy of gas-phase molecules from the high-mass star-forming region IRAS 23385+6053