A diboron compound represented by Formula I R 1 - X - R 2 in which Formula I, X represents a linker of Formula Ia: wherein ---- represents a covalent bond towards R 1 or R 2; W represents -OH, -NHCH 2 COOH, -NHCH 2 CH 2 COOH, -NHCH 2 CH 2 CH 2 COOH, or -NHCH(COOH)CH 2 CH 2 COOH (the latter representing an L-gamma-Glu or a D-gamma-Glu residue); or X represents a linker of Formula Ib: wherein, ---- represents a covalent bond towards R 1 or R 2; and R 3 represent -(CH 2) m (C=O)-W; wherein m represents an integer in the range of 1 to 4; and W represents OH, NHCH 2 COOH; NHCH 2 CH 2 COOH; NHCH 2 CH 2 CH 2 COOH; or NHCH(COOH)CH 2 CH 2 COOH (the latter representing an L-gamma-Glu or a D-gamma-Glu residue); or X represents a linker of Formula Ic: which represents a D- or an L -amino acid form; and wherein, ---- represents a covalent bond towards R 1 or R 2; n represents an integer in the range of 1 to 4; W represents -OH, -NHCH 2 COOH, -NHCH 2 CH 2 COOH, -NHCH 2 CH 2 CH 2 COOH, or -NHCH(COOH)CH 2 CH 2 COOH (the latter representing an L-gamma-Glu or a D-gamma-Glu residue); or wherein X represents a linker of Formula Id: which represents a R,R or S,S, or R,S or R,S stereoisomer of the 3,4-diamino-pyrrolidine; wherein, ---- represents a covalent bond towards R 1 or R 2; R 4 represents -(C=O)(CH 2) p (C=O)-W; wherein p represents an integer in the range of 1 to 4; W represents -OH, -NHCH 2 COOH, -NHCH 2 CH 2 COOH, -NHCH 2 CH 2 CH 2 COOH, or -NHCH(COOH)CH 2 CH 2 COOH (the latter representing an L-gamma-Glu or a D-gamma-Glu residue); or X represents a linker of Formula Ie: wherein, ---- represents a covalent bond towards R 1 or R 2; or X represents a linker of Formula If: wherein, ---- represents a covalent bond towards R 1 or R 2; or X represents a linker of Formula Ig: wherein, ---- represents a covalent bond towards R 1 or R 2; or X represents a linker of Formula Ih: wherein, ---- represents a covalent bond towards R 1 or R 2; or X represents a linker of Formula Ii: wherein, ---- represents a covalent bond towards R 1 or R 2; and W represents -OH, -NHCH 2 COOH, -NHCH 2 CH 2 COOH, -NHCH 2 CH 2 CH 2 COOH, or -NHCH(COOH)CH 2 CH 2 COOH (the latter representing an L-gamma-Glu or a D-gamma-Glu residue); and R 1 and R 2, which may be identical or different, each represents a group of Formula IIa or IIb: wherein, one to four Y represents H; and none, one or two of Y represents F, Cl, CF 2, CF 3, SF 5, OCF 3, SO 2 CH 3 and/or SO 2 CF 3; and one Y represents (a covalent bond representing) the attachment point to X of Formula I; and when X is Formula Ie, If, Ig or Ih, one Y in either R 1 or R 2 represents -(C=O)-W, where W represents -OH, -NHCH 2 COOH, -NHCH 2 CH 2 COOH, -NHCH 2 CH 2 CH 2 COOH, or -NHCH(COOH)CH 2 CH 2 COOH (the latter representing an L-gamma-Glu or a D-gamma-Glu residue). X represents a linker of Formula Ia: wherein ---- represents a covalent bond towards R 1 or R 2; W represents -OH, -NHCH 2 COOH, -NHCH 2 CH 2 COOH, -NHCH 2 CH 2 CH 2 COOH, or -NHCH(COOH)CH 2 CH 2 COOH (the latter representing an L-gamma-Glu or a D-gamma-Glu residue); or X represents a linker of Formula Ib: wherein, ---- represents a covalent bond towards R 1 or R 2; and R 3 represent -(CH 2) m (C=O)-W; wherein m represents an integer in the range of 1 to 4; and W represents OH, NHCH 2 COOH; NHCH 2 CH 2 COOH; NHCH 2 CH 2 CH 2 COOH; or NHCH(COOH)CH 2 CH 2 COOH (the latter representing an L-gamma-Glu or a D-gamma-Glu residue); or X represents a linker of Formula Ic: which represents a D- or an L -amino acid form; and wherein, ---- represents a covalent bond towards R 1 or R 2; n represents an integer in the range of 1 to 4; W represents -OH, -NHCH 2 COOH, -NHCH 2 CH 2 COOH, -NHCH 2 CH 2 CH 2 COOH, or -NHCH(COOH)CH 2 CH 2 COOH (the latter representing an L-gamma-Glu or a D-gamma-Glu residue); or wherein X represents a linker of Formula Id: which represents a R,R or S,S, or R,S or R,S stereoisomer of the 3,4-diamino-pyrrolidine; wherein, ---- represents a covalent bond towards R 1 or R 2; R 4 represents -(C=O)(CH 2) p (C=O)-W; wherein p represents an integer in the range of 1 to 4; W represents -OH, -NHCH 2 COOH, -NHCH 2 CH 2 COOH, -NHCH 2 CH 2 CH 2 COOH, or -NHCH(COOH)CH 2 CH 2 COOH (the latter representing an L-gamma-Glu or a D-gamma-Glu residue); or X represents a linker of Formula Ie: wherein, ---- represents a covalent bond towards R 1 or R 2; or X represents a linker of Formula If: wherein, ---- represents a covalent bond towards R 1 or R 2; or X represents a linker of Formula Ig: wherein, ---- represents a covalent bond towards R 1 or R 2; or X represents a linker of Formula Ih: wherein, ---- represents a covalent bond towards R 1 or R 2; or X represents a linker of Formula Ii: wherein, ---- represents a covalent bond towards R 1 or R 2; and W represents -OH, -NHCH 2 COOH, -NHCH 2 CH 2 COOH, -NHCH 2 CH 2 CH 2 COOH, or -NHCH(COOH)CH 2 CH 2 COOH (the latter representing an L-gamma-Glu or a D-gamma-Glu residue); and R 1 and R 2, which may be identical or different, each represents a group of Formula IIa or IIb: wherein, one to four Y represents H; and none, one or two of Y represents F, Cl, CF 2, CF 3, SF 5, OCF 3, SO 2 CH 3 and/or SO 2 CF 3; and one Y represents (a covalent bond representing) the attachment point to X of Formula I; and when X is Formula Ie, If, Ig or Ih, one Y in either R 1 or R 2 represents -(C=O)-W, where W represents -OH, -NHCH 2 COOH, -NHCH 2 CH 2 COOH, -NHCH 2 CH 2 CH 2 COOH, or -NHCH(COOH)CH 2 CH 2 COOH (the latter representing an L-gamma-Glu or a D-gamma-Glu residue).