Abstract: There is provided a compound having Formula I R1—Z—R2 ??Formula I wherein R1 is a group selected from optionally substituted fused polycyclic groups, substituted alkyl groups, branched alkyl groups, and optionally substituted cycloalkyl groups Z is a linker which is or comprises a carbonyl group or a isostere of a carbonyl group R2 is selected from optionally substituted aromatic rings and optionally substituted heterocyclic rings wherein (a) R2 is a 2-substituted thiophene group, and/or (b) Z is a group of the formula —C(?O)—CR3R4—X—(CR5R6)n-, wherein X is selected from NR7, S, O, S?O, and S(?O)2, wherein n is 0 or 1 and/or (c) R1 is an adamantyl group and Z is or comprises an amide group, and/or (d) R1 is an adamantyl group and Z is or comprises a group of the formula —(CR8R9)p- NR10—S(?O)2—(CR11R12)q-, wherein p is 0 or 1 and q is 0 or 1 and/or (e) R1 is an adamantyl group and Z is or comprises a group of the formula —(CR13R14)v-Y—(CR15R16)w- where Y is a heteroaryl group in which a bond in the hetero