Hao Feng, Le Cai
This study provides a comprehensive review of novel organic small molecules with plant growth-promoting activity that were reported internationally between 2005 and 2026. It aims to offer a systematic molecular template for agricultural chemistry research. The study systematically reviews three major categories: natural, semisynthetic, and synthetic molecules. Among the molecules, 103 are natural molecules, 19 are semi-synthetic molecules and 71 are synthetic molecules. It highlights the functional diversity of these molecules in growth promotion, fruit ripening and yield enhancement, seed germination promotion, and plant resistance enhancement. Natural molecules display novel and unique structures, whereas semi-synthetic molecules enhance core activity through chemical optimization. Synthetic molecules provide a versatile platform for targeted molecular design. This review lays a solid foundation for the rapid identification of promising active molecules in agricultural chemistry. It helps reduce redundant studies and supports the development and application of novel plant growth regulators. • Covers natural, semisynthetic, and synthetic molecules with plant growth-promoting activity reported from 2005 to 2026. • Molecules are grouped by function: growth promotion, fruit ripening and yield, seed germination, and stress resistance. • Provides a curated collection of precursor molecules with defined structures and verified activity for agrochemical research. • Summarizes mechanisms of action to help reduce redundant screening and support the development of new plant growth regulators.