Despite the therapeutic potential of 5-HT2A receptor targeting, drug development remains challenging due to poor ligand selectivity. Many 'selective' ligands often display nanomolar activity across multiple GPCRs and can possess distinct pharmacological profiles at individual receptors. Using both label-free impedance (xCELLigence) and Ca2+ mobilisation (FLIPR) assays, we reveal divergent pharmacological behaviours of established 5-HT2 receptor ligands. This work reiterates the challenges surrounding 5-HT2A drug discovery and highlights the importance of orthogonal assay approaches to fully profile ligand pharmacology.