A newly identified small molecule could help grafted plants establish a stronger first connection, potentially expanding grafting in crops that are difficult to join. By screening 3,000 synthetic compounds, researchers discovered graft-promoting molecule 1 (GPM1), which increased early tissue adhesion in several legume species and in a cross-species graft combination. The compound also improved graft performance in two plants outside the legume family. Molecular and anatomical evidence indicates that GPM1 promotes cell-wall remodeling and callus-cell expansion at the cut surface without triggering the broad auxin response seen with conventional hormone treatment. The findings introduce a targeted chemical strategy for making early graft healing more reliable.