N-Boc-N-bis(PEG4-Propargyl) is a bifunctional PEG compound containing two terminal alkynes that are combined together at a Boc-protected secondary amine. Terminal alkynes are most commonly used in copper click chemistry with azides to form stable triazoles with the target molecule. The secondary amine may be deprotected under acidic conditions to allow for alkylation at that position, increasing the molecule’s structural complexity. The use of a central amine also allows for hydrogen bonding, further increasing this compound’s water solubility.