fluorescence sensing abilities to iron (III), cobalt (II), nickel (II), zinc (II) and copper (II) ions were examined in polyvinylchloride matrix. Thiophene-based oxazol-5-one derivatives revealed high sensitivity and selectivity toward iron (III). A good linearity with a correlation coefficient of 0.99 was observed in the concentration range of 1.0 × 10−7 to 1.0 × 10−3 M iron (III) for 2-phenyl-4-(2-thienylme