Some lipids such as sphingosine and diacylglycerol are potent signaling effectors. However, comprehensive investigations of their bioactive actions are often hampered by a lack of tools that can be used in living cells. Here, we present chemically modified lipids that allow investigation of acute lipid signaling, lipid metabolism, lipid−protein interactions, and lipid localization by using a single probe for each target lipid. Equipped with a caging group, the lipid probe is biologically inactive, until activated by a flash of light. A second photoreaction cross-links the probe to protein interactors that may subsequently be analyzed by mass spectrometry or fluorescence/electron microscopy. We envision that this versatile design will be central to unraveling complex lipid signaling networks.