To elucidate differences in nutritional components and glucosinolates between broccoli and lacinato kale leaves, and to promote consumption of broccoli and kale leaves for human nutrition, food development, and by-product utilisation, this study used UPLC-MS/MS and HPLC for both qualitative and quantitative analyses of their metabolome and glucosinolate profiles. In broccoli leaves, 11 glucosinolates were identified, notably including high concentrations of glucoraphanin, glucobrassicin, and neoglucobrassicin. In contrast, lacinato kale leaves contained seven glucosinolates, with glucoraphasatin being the most abundant. Moreover, our analysis revealed 644 metabolites, 87 of which were differentially expressed between these crucuiferous vegetables. These findings not only offer new insights into nutritional value but also highlight their potential as plant chassis for the biosynthesis of valuable products, thereby broadening food diversity and improving by-product utilisation.