The absorption spectrum of thin K_(2)ZnI_(4) films has been investigated in the range of 3-6 eV at temperatures from 90 to 340 K. It is established that this compound belongs to direct-gap insulators; low-frequency exciton excitations are localized in the ZnI_(4) lattice layers and have a quasi-two-dimensional character. The spectral analysis revealed the existence of two K_(2)ZnI_(4) modifications, which presumably belong to the monoclinic (I) and orthorhombic (II) phases. The temperature dependences of the spectral position and halfwidth of the low-frequency exciton band in K_(2)ZnI_(4) revealed the existence of first-order phase transitions at 215 and 225 K in the monoclinic and orthorhombic phases, respectively.
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