Abstract: Provided herein is a compound having a structure of Formula (I): (Formula (I)) wherein: D is S, O or an ester; p is 1 to 6; L1 and/or L2 are independently linear or branched C1-C30 alkyl, optionally having one or more C?C double bonds of E or Z geometry; and wherein: if D is S then L1 and/or L2 are unsubstituted or substituted with one or more S; and if D is O or an ester, then L1 and/or L2 are substituted with one more S. The compound may be formulated in a lipid nanoparticle for use in the delivery of charged cargo such as nucleic acid. Further provided are methods for making the compound.