N-(Azido-PEG1)-N-bis(PEG2-t-butyl ester) is a small branched PEG linker with an azide and two t-butyl esters. Each t-butyl ester may be deprotected and used in coupling with nucleophiles such as primary amines or alcohols. The azide group is available for click chemistry with alkynes or strained cyclooctynes.