The name/synonym for ligand C2E (curated from ChEBI, PubChem, and PDB databases):

1C-DI-GMP
2GUANOSINE 3',5'-CYCLIC MONOPHOSPHATE
3CYCLIC DINUCLEOTIDE DI-GMP
4BIS(3',5')-CYCLIC DIGUANYLIC ACID
5C-(GPGP)
6GUANYLYL-(3'->5')-3'-GUANYLIC ACID, CYCLIC 3'->5'''-NUCLEOTIDE
7CYCLIC DIGUANYLIC ACID
8CYCLIC-BIS(3',5')DIGUANYLIC ACID
93',5'-CYCLIC DI-GMP
10CYCLIC-BIS(3'->5') DIMERIC GMP
11BIS-(3'-5')-CYCLIC DIMERIC GUANOSINE MONOPHOSPHATE
12CGPGP
13C-DIGMP
14CYCLIC DI-GMP
159,9'-[(2R,3R,3AS,7AR,9R,10R,10AS,14AR)-3,5,10,12-TETRAHYDROXY-5,12-DIOXIDOOCTAHYDRO-2H,7H-DIFURO[3,2-D:3',2'-J][1,3,7,9,2,8]TETRAOXADIPHOSPHACYCLODODECINE-2,9-DIYL]BIS(2-AMINO-1,9-DIHYDRO-6H-PURIN-6-ONE)
16CYCLIC DI-3',5'-GUANYLIC ACID
179,9'-[(2R,3R,3AS,5S,7AR,9R,10R,10AS,12S,14AR)-3,5,10,12-TETRAHYDROXY-5,12-DIOXIDOOCTAHYDRO-2H,7H-DIFURO[3,2-D:3',2'-J][1,3,7,9,2,8]TETRAOXADIPHOSPHACYCLODODECINE-2,9-DIYL]BIS(2-AMINO-1,9-DIHYDRO-6H-PURIN-6-ONE)
18CYCLIC DIGUANOSINE MONOPHOSPHATE