Hydrogen sulfide (H2S) has recently been identified as a biological response modifier. Here, we report the design and synthesis of a novel fluorescence probe for H2S, HSip-1, utilizing azamacrocyclic copper(II) ion complex chemistry to control the fluorescence. HSip-1 showed high selectivity and high sensitivity for H2S, and its potential for biological applications was confirmed by employing it for fluorescence imaging of H2S in live cells.