Inflammation imaging is central to the diagnosis and monitoring of the progression of a vast range of diseases. As is suggested by the strong upregulation in the presence of biological insults, the P2X7 receptor plays a fundamental role in the inflammatory cascade. In this context, the development of a centrally acting Positron Emission Tomography (PET) tracer is a promising step towards harnessing the therapeutic and diagnostic potential offered by this target. In this work, inspired by the known antagonist A-804598, a set of four novel 18F-labelled PET ligands were designed, synthesised and evaluated in in vitro and in vivo models of neuroinflammation. The tracers were synthesised via novel trisubstituted guanidine and copper alkyne-azide cyclised intermediates. Multi-step radiofluorinations were carried out with the use of the [18F]fluorobenzyl amine synthon and “click” radiochemical techniques employing [18F]fluoroethyl amine. The compounds were evaluated in vitro with radioligand binding and calcium influx assays. Further validation was carried out in a hypoxic ischaemic mouse tissue model of neuroinflammation and in lipopolysaccharide-injected rats. This work generated four novel PET tracers, including one able to recognise inflamed tissues in vivo. These developments could form an important part of a drug discovery programme and may lead to an improved understanding of neuroinflammatory diseases and the treatment thereof.