This study investigates the structural pharmacology and therapeutic potential of 5-methoxytryptamines, including 5-MeO-DMT, focusing on their interactions with 5-HT1A and 5-HT2A receptors. The research combines structural biology, medicinal chemistry, and behavioral studies to elucidate the molecular mechanisms underlying the pharmacological effects of these compounds. Cryo-electron microscopy (cryo-EM) structures of 5-HT1A-Gi complexes bound to 5-MeO-DMT and LSD reveal detailed insights into their binding modes and interactions with the receptor. These structures show that 5-MeO-DMT and LSD bind to the orthosteric binding pocket (OBP) of 5-HT1A, with 5-MeO-DMT binding deeper than serotonin. The structures also highlight distinct interactions, such as a hydrogen bond between the indole nitrogen of the drugs and T121, which is not observed with serotonin. Structure-activity relationship (SAR) analyses of 5-methoxytryptamines at both 5-HT1A and 5-HT2A receptors reveal molecular determinants of signaling potency, efficacy, and selectivity. The study shows that a 5-HT1A-selective 5-MeO-DMT analogue retains anxiolytic and antidepressant-like activity in socially defeated animals while lacking hallucinogenic-like effects. The research also compares the structural interactions and in vitro pharmacology of 5-MeO-DMT and its analogues with LSD and clinically used 5-HT1A agonists, highlighting the importance of 5-HT1A in the therapeutic effects of these compounds. In vivo studies using 4-F,5-MeO-PyrT, a 5-HT1A-selective analogue of 5-MeO-DMT, demonstrate its high potency and selectivity for 5-HT1A, with minimal effects on 5-HT2A. The compound shows significant anxiolytic and antidepressant-like effects in a chronic social defeat model, indicating its potential as a therapeutic agent. The study also highlights the role of 5-HT1A in mediating the therapeutic effects of 5-MeO-tryptamines, suggesting that these compounds may have therapeutic applications for neuropsychiatric disorders. The findings underscore the importance of 5-HT1A in the pharmacological effects of tryptamines and highlight the potential of 5-HT1A-targeted therapies for neuropsychiatric disorders. The study provides a structural and functional framework for the development of new tryptamine-based drugs with tailored pharmacological activities and selectivity for 5-HT1A over 5-HT2A. The results suggest that 5-HT1A activation may play a key role in the therapeutic effects of 5-MeO-tryptamines, offering new insights into the molecular mechanisms underlying their actions.This study investigates the structural pharmacology and therapeutic potential of 5-methoxytryptamines, including 5-MeO-DMT, focusing on their interactions with 5-HT1A and 5-HT2A receptors. The research combines structural biology, medicinal chemistry, and behavioral studies to elucidate the molecular mechanisms underlying the pharmacological effects of these compounds. Cryo-electron microscopy (cryo-EM) structures of 5-HT1A-Gi complexes bound to 5-MeO-DMT and LSD reveal detailed insights into their binding modes and interactions with the receptor. These structures show that 5-MeO-DMT and LSD bind to the orthosteric binding pocket (OBP) of 5-HT1A, with 5-MeO-DMT binding deeper than serotonin. The structures also highlight distinct interactions, such as a hydrogen bond between the indole nitrogen of the drugs and T121, which is not observed with serotonin. Structure-activity relationship (SAR) analyses of 5-methoxytryptamines at both 5-HT1A and 5-HT2A receptors reveal molecular determinants of signaling potency, efficacy, and selectivity. The study shows that a 5-HT1A-selective 5-MeO-DMT analogue retains anxiolytic and antidepressant-like activity in socially defeated animals while lacking hallucinogenic-like effects. The research also compares the structural interactions and in vitro pharmacology of 5-MeO-DMT and its analogues with LSD and clinically used 5-HT1A agonists, highlighting the importance of 5-HT1A in the therapeutic effects of these compounds. In vivo studies using 4-F,5-MeO-PyrT, a 5-HT1A-selective analogue of 5-MeO-DMT, demonstrate its high potency and selectivity for 5-HT1A, with minimal effects on 5-HT2A. The compound shows significant anxiolytic and antidepressant-like effects in a chronic social defeat model, indicating its potential as a therapeutic agent. The study also highlights the role of 5-HT1A in mediating the therapeutic effects of 5-MeO-tryptamines, suggesting that these compounds may have therapeutic applications for neuropsychiatric disorders. The findings underscore the importance of 5-HT1A in the pharmacological effects of tryptamines and highlight the potential of 5-HT1A-targeted therapies for neuropsychiatric disorders. The study provides a structural and functional framework for the development of new tryptamine-based drugs with tailored pharmacological activities and selectivity for 5-HT1A over 5-HT2A. The results suggest that 5-HT1A activation may play a key role in the therapeutic effects of 5-MeO-tryptamines, offering new insights into the molecular mechanisms underlying their actions.