The synthesis of two long-chain homologues of the fluorescent membrane probes TMA-DPH and DPHpPC is described. The long-chain phosphatidylcholine could be synthesized from palmitoyl-lysophosphatidylcholine and 21-(diphenylhexatrienyl) henicosanoic acid only when the promoting agent was 1, 1′-thionyldiimidazole.