N-trans-cinnamoyltyramine (NTCT) has been identified from an allelopathic Vietnamese rice accession OM 5930. The study employed a rigorous analysis of NTCT’s effects on shoot and root growth across multiple plant species. Notably, barnyardgrass and red sprangletop exhibited significant reductions in shoot and root growth with increasing NTCT concentrations, indicating a dose-dependent response (from 0.024 μM to 24 μM). Weedy rice accessions PI 653426 and PI 653431 also display dose-dependent effects, with notable declines in both shoot and root growth (from 0.25 μM to 15.6 μM and from 0.44 μM to 85.8 μM, respectively). Additionally, NTCT demonstrates potent inhibitory effects on palmer amaranth, timothy, canola, cress, and lettuce, with increasing concentrations leading to substantial reductions in growth across all species (Average from 2.4 μM). Linear regression analysis reveals the ED50 values for NTCT, providing critical insights into the concentration required for 50% growth inhibition in each species. These values range from 0.19 to 166.1 μM for shoots and from 1.74 to 33.07 μM for roots, highlighting the varying sensitivities among the test plant species. The findings underscore NTCT’s efficacy in suppressing the growth of a wide range of weeds, including both grasses and broadleaf species. The compound shows promise for sustainable weed management practices, particularly in addressing herbicide-resistant weeds in diverse ecological settings. By elucidating NTCT’s inhibitory and species-specific responses, this study contributes valuable insights to the development of eco-friendly herbicidal agents for effective weed control