SDA maleimide is an excellent heterobifunctional crosslinker that effectively combines two established chemical modalities, thiol-selective maleimide chemistry and diazirine-based photoaffinity labeling. Its maleimide group forms covalent thioether bond with thiol groups on one protein, while the diazirine moiety exhibit efficient photoreactivity towards amino acid side chains or peptide backbones on another protein within the prescribed spacer arm distance, once activated by long-wave UV light (330-370 nm). SDA's two-step chemical crosslinking process can be easily activated using conventional laboratory UV lamps, streamlining experimental protocols. Furthermore, SDA crosslinkers demonstrate excellent photostability even under standard laboratory lighting conditions, eliminating the need for a light-restricted environment. Given that diazirine maleimide is membrane-permeable, it might be suited for in vivo intracellular and intramembrane conjugations and investigating protein-protein interactions.