There are four ways the oxygen vertices are paired (1 + , 1 -, 2 + and 2 -), each with 16 possible ellagate orientations (xxxx where each x can be a or b), resulting a total of 64 possible chiral isomers or 32 enantiomeric pairs (Supplementary Fig. ). Of these 32, only five have been observed so far amongst the reported MOFs (2aaaa, 2aaba, 1bbba, 2bbaa, 2baab) as illustrated in Fig. .