Novel ethyl thiourea compounds 1a-1f have been synthesized in good to high yields. The structure of all compounds were identified using FT-IR, 1 H NMR, 13C NMR spectroscopies, and ESI-Mass spectrometry. The compound 1-ethyl-3-(3-methoxyphenyl) thiourea 1e was obtained in crystalline form by recrystallization from DMSO. Single crystal X-ray analysis revealed that 1e molecule crystallized in a monoclinic crystal system with space group of P21/n and the unit cell dimensions are a = 11.0797(7) Å, b = 8.6081(6) Å, c = 11.9698(7) Å, a = 90°, b =104.543(2)°, g = 90°, Z = 4 and V = 1105.04(12) Å 3 .The preliminary optical sensor properties for metal ions of 1a, 1b and 1d were investigated using naked-eye. The results determined that all compounds have the ability as naked eye sensors for mercury (Hg) and argentum (Ag) metal ions.