Mal-Cz is a maltose-derived fluorescence-on imaging probe for the detection of E. coli and Staphylococcus aureus. It contains an Azide group and can undergo copper-catalyzed azide-alkyne cycloaddition reaction (CuAAc) with molecules containing Alkyne groups. It can also undergo strain-promoted alkyne-azide cycloaddition (SPAAC) reactions with molecules containing DBCO or BCN groups.