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The singlet-triplet absorption spectrum of crystalline $1,1\prime$-diethyl-$2,2\prime$-cyanine iodide has been obtained. The absorption origin consists of two lines separated by $\sim 4.0$ $cm-1$. Zeeman spectra were used to assign the higher energy, more intense line to the $Au$ factor group state and the lower energy line to the $Bu$ factor group state. Emission spectra have been obtained on both dilute and concentrated solid solutions of the dye. The results from the concentrated samples indicate that the largest excitation-transfer interaction between crystallographically equivalent molecules is less than $1cm-1$. This work represents the first spectroscopic characterization of the triplet state of an ionic dye crystal.