Chemical synapses enable effective communication within neuronal circuits through a generalised presynaptic neurotransmitter release machinery and specialised postsynaptic receptor clusters. In the mammalian brain, type A γ-aminobutyric acid receptors (GABAARs), members of the pentameric ligand-gated ion channel (pLGIC) family, are the principal mediators of inhibitory neurotransmission. While structural insights have been gained on the isolated receptors, the neuronal context presents additional layers of complexity, with multiple factors influencing the targeting, anchoring, and residence time of GABAARs at synapses. In the absence of structural information, however, the principles governing selective capture of specific receptor subsets and the organisation of inhibitory synapses remain elusive. In this seminar, I will present a series of cryogenic electron microscopy (cryo-EM) structures of a synaptic GABAAR bound to the auxiliary protein GARLH4 and the transmembrane region of synaptic adhesion molecule neuroligin-2, in multiple states across the receptor gating cycle. These structural ensembles reveal dynamic coupling principles and uncover unexpected roles for sterols, phospholipids, and post-translational modifications in complex organisation, as well as determinants that discriminate between synaptic and extrasynaptic receptor variants. Structure-guided mutational analyses corroborate the functional relevance of these observations. I will further show how our structures explain in situ observations of dimeric GABAAR assemblies and demonstrate how cryo-EM reconstructions of a noncanonical receptor complex containing two sets of auxiliary proteins may serve as a nucleation unit for higher-order, mesophasic receptor organisation at inhibitory synapses. Together, these findings define an organisational framework for prototypical inhibitory neurotransmitter receptor complexes and pave the way for dissection of GABAergic signalling mechanisms in physiological contexts.