Malachite Green (MG) organic dye thin film was prepared by simple drop casting method. Microstructural property of MG layer was investigated by Scanning Electron Microscopy (SEM). SEM image indicated that MG organic thin layer was formed from nanoclusters. Later, it was fabricated Ag/Malachite Green(MG)/p-InP diodes by drop cast method. The barrier height (BH) and ideality factor by using I-V characteristics for the device were found as 0.75 eV and 1.68. By using the Norde method, the BH and the resistance of neutral region of the device were extracted as 0.80 eV and 1.17x104 Ω. The interfacial states concentration of the device has been seen to decrease from 2.79×1013 eV-1 cm-2 to 5.80×1012 eV-1 cm-2 . By using capacitance-voltage technique, the values of the built-in voltage, BH and semiconductor doping density were found as 1.22 V, 0.83 eV and 1.87x1017 cm-3 for the Ag/MG/p-InP diode, respectively.