Mustard and rapeseed arevital oilseed crops in India; however, both national and regional yields are substantially below their genetic potential, particularly among resource-constrained smallholders. In Sepahijala district of Tripura, North-east India, farmers typically achieve approximately 7–8 q/ha, which is far lower than the 14 q/ha potential of enhanced cultivars. To mitigate this yield gap, we executed Cluster Frontline Demonstrations (CFLDs) utilising enhanced mustard varieties and methodologies from 2020 to 2025. Over a span of five years, 206 farmers on 130 hectares engaged in on-farm demonstrations utilising high-yielding cultivars (NRCHB-101 and PM-27) with optimal agronomic practices, training, and input assistance. The yields from the enhanced technology averaged 10.3–10.8 q/ha compared to 7.2–7.9 q/ha in farmers' plots, representing a 34–43% increase. This resulted in markedly increased profitability, with demonstrators achieving net income earnings of Rs 26,700–33,250 per hectare compared to Rs 15,346–22,828 per hectare under conventional practices. The benefit–to–cost ratios improved from around 1.6 to 1.8. The observed improvements align with those from other CFLD research, such as a 36% increase in Tripura and approximately 28–30% in Uttar Pradesh, highlighting significant technological and extension gaps of approximately 3.3–3.8 q/ha. Socioeconomic surveys indicated that participants were predominantly older (>50 years), low-literacy, marginal farmers, which constrained the swift adoption of all approaches. Reported key constraints included delayed sowing, seed availability, pest control, and irrigation shortages, highlighting issues faced by both farmers and extension services. The instance illustrates the efficacy of participatory demonstrations in enhancing mustard output and income, while also emphasising ongoing adoption obstacles. Future expansion will necessitate resolving input logistics, maintaining training continuity, and implementing supportive policies to uphold enhanced practices.