The second messenger diacylglycerol (DAG) plays a central role in the signal transduction of G-protein coupled receptors and receptor tyrosine kinases by binding to C1 domain of effector proteins. C1 domain was first identified in protein kinase C (PKC) which comprises a family of ten isoforms that play roles in diverse cellular processes such as proliferation, apoptosis and differentiation. Aberrant signaling through PKC isoforms and other C1 domain-containing proteins has been implicated in several pathological disorders. Drug discovery concerning C1 domains has exploited both natural products and rationally designed compounds. Currently, molecules from several classes of C1 domain-binding compounds are in clinical trials; however, still more have the potential to enter the drug development pipeline. This review gives a summary of the recent developments in C1 domain-binding compounds.