The synthesis of N-arylamide phosphonates and related arylether and arylamine analogues provided potent, subtype-selective agonists and antagonists of the five known sphingosine 1-phosphate (S1P) receptors (S1P(1-5)). To this end, the syntheses of phosphoserine mimetics-selectively protected and optically active phosphonoserines-are described. In vitro binding assays showed that the implementation of phosphonates as phosphate mimetics provided compounds with similar receptor binding affinities as compared to their phosphate precursors. meta-substituted arylamide phosphonates were discovered to be antagonists of the S1P(1) and S1P(3) receptors. When administered to mice, an antagonist blocked the lymphopenia evoked by a S1P receptor agonist and caused capillary leakage in both lung and kidney.