The taxonomic richness of medicinal plants in Pakistan can foster notable economic contributions through medicinal, industrial and environmental applications. The release of allelochemicals from medicinal plants have metamorphosed the discourse of research on medicinal plants. The allelopathy epitomizes stimulatory or inhibitory interactions among organisms due to their inherent ability to forego biological invasions and impede biological activities by release of certain chemicals. This study extended to the allelopathic effect of 221 species collected from different regions of Pakistan. The cardinal objective was to assess the allelopathic effect of medicinal plants collected from different regions of Pakistan using dish pack method. As the dish pack method allows the assessment of allelopathic effect due to volatile secondary metabolites released from different plants. Hence, the germination and growth of lettuce was tested against selected plant species. The findings of this study envisaged the Boerhavia procumbens for strong inhibitory effect and Plectranthus rugosus for strong stimulatory effect due to release of volatile allelochemicals. The results hereby envisions future applications of allelopathy in sustainable agriculture, industry, weed management, agro-environment conservation, food security and soil conservation. The second objective of this study was to explore allelopathic effect of medicinal plants on the germination and seedling growth of lettuce using sandwich method. The 207 plant species had been tested using sandwich method to assess allelopathic effect of leachates of different parts of plants on lettuce seeds and provide baseline information for exploration of medicinal plants for economic benefits. The results of this study identifies 4 plants having strong inhibitory effect, 14 plants with medium inhibitory and 13 plants of low inhibitory effect on the lettuce seeds. Boerhavia procumbens exhibited the strongest inhibitory allelopathic effect and Viburnum grandiflorum presented strong stimulatory effect on the growth of lettuce seeds. The allelopathic effects of aqueous extract of different plant species on wheat (Triticum aestivum L.), Lettuce (Lactuca sativa L.) and maize (Zea mays L.) were also assessed in this study. We have selected nine plant species (Boerhavia procumbens Banks ex Roxb., Jacaranda mimosifolia D. Don, Datura metel L., Asparagus adscendens Roxb., Plectranthus rugosus Wall. ex Benth. Parthenium hysterophorus L., Arisaema triphyllum (L.) Schott, Crotalaria medicaginea DC. and Amaranthus viridis L) and apply their aqueous extract directly to crop seeds as well as through the soil medium to assess their allelopathic effect in both conditions. The results apprehended that the aqueous extracts of all the selected species revealed significant inhibitory effect on germination and growth of wheat, maize and lettuce as compared to the aqueous extracts applied to the soil. However, lettuce was more influenced from the inhibitory effect followed by maize and wheat in the soil irrigated with the aqueous extracts of selected species. Hence, the diversified allelopathic effects of plants have the potential to improve weed management, sustainable agriculture, food production as well as medicinal, industrial and environmental applications