In this issue of Chemistry and Biology, Rizvi and colleagues indentify a small molecule that inhibits formin-mediated actin assembly. Together with recently characterized inhibitors of the Arp2/3 complex (Nolen et al., 2009) and formins (Gauvin et al., 2009), these small molecules provide useful laboratory tools to dissect the link between actin nucleators and actin-based structures in living cells.