Emerging adulthood (18-25 years) represents a risky time for mental health and substance use. Emerging adults are particularly susceptible to problematic patterns of substance use, especially if they experience anxiety and/or depression and use substances as a way to cope with such issues. However, many mental health treatments do not address substance use. We developed an ecological momentary assessment and intervention (EMA/EMI) to specifically target the motive of drinking to cope with anxiety/depression. : Project CHOICE was a 6-week intervention that paired in-person normative feedback with daily EMA and, if an individual reported negative affect and intent to drink, an EMI was immediately sent to their phone (a personally-chosen coping skill). We recruited  = 20 (55% female, mean age 21.74, 85% Caucasian and 75% non-Hispanic/Latino) individuals from a psychiatric partial hospitalization program for a 6-week open trial of the CHOICE intervention and re-assessed at the 6-week follow-up point. : Results indicated that drinking variables and coping motives were highly correlated at baseline. Days of drinking, alcohol-related problems, and coping motives significantly decreased over time following the intervention. Results indicated high levels of feasibility and acceptability. : This open pilot represents a feasible, acceptable, and promising direction in delivering interventions in the moment when risk is highest, utilizing smartphone capabilities.