Synthesis of Leishmania mRNA 5'-cap analogs, m(7) Gpppm(2)(6)AmpAm (cap-2), and m(7) Gpppm(2)(6)AmpAmpCm (cap-3) is reported. Binding affinities of those cap analogs for LeishIF4E Proteins were determined using fluorescence spectroscopy. Cap-3 showed similar affinity to LeishIF4Es compared to the mature trypanosomatids cap structure (cap-4).