2-Methyl-4-(1-(naphthalen-2-yl)ethylidene)oxazol-5(4H)-one 2 was used as precursor for the preparation of some novel (1-(4-substituted)-2-methyl-4-(1-naphthalen-2-yl)ethylidene)-1H-imidazol-5(4H)-one derivatives 4a, b and other derivatives 3a,b, 5-12. Furthermore, the preparation of thieno[2,3-d]pyrimidin-4(3H)-one derivative 16,17 and 4-iminothieno[2,3-d] pyrimidin-3-ylamine derivative 18, 19 is described starting from 2-aminothiophen-3-carbonitrile derivative 15a. Some of the prepared products revealed a promising antioxidant activity by using 1,1-diphenyl-2,2-picryl hydrazyl free radical (DPPH) method.