4-fold chemical compounds
Assuming the "4-fold" is not referring to "use four equivalents of X per molecular function Y to obtain the intended chemical reaction", it refers more often to a specical class of star shaped polymers, called dendrimers.  Commonly, around a nucleous, you have several times the same chemical group, as, for example, drawn here:



In this example, instead of a linear chain of polyethylene glycol (PEG), four branches are stitched together; the fourth example may relate the closest to your question.

Source of the picture: Zhu, Biomaterials 31 (2010) 4639-4656, doi: 10.1016/j.biomaterials.2010.02.044