The present study focused on pollen germination and pollen tube length in selected plants species for its reproductive success. The aspects of allelopathy, allelochemicals, mechanism of allelopathy of weed plants, and their impact on crops are discussed in this review paper. An overview of the mode of action of the weed and different strategies and their direct and indirect impact on the overall agricultural system were analyzed. After the passing of the 20th century, the curiosity of the researchers took a remarkable work in comparison to the last decades of the 19th century that was needed too mainly because there was little awareness to the farmers of farming. They are using old practices and synthetic agrochemicals still now, thus having a long-lasting negative impact on the overall factors that have the ability to keep ecosystem balance. There are advanced agriculture techniques and tools that are explored day by day with the reference to sustainable problems. Allelochemicals are present in all types of tissues and are released by a variety of mechanisms, including decomposition of residues, volatilization, and root exudation into the rhizosphere. Allelochemical its structure and mode of action are different and may offer a potential for the future development of herbicide. In this context, there is the discussion of the invasiveness of Chenopodium murale (L.) on certain selected crop species and the aggressiveness of different plant species on the same.