Thiazole and phenoxyacetic acid are key moieties in many natural and synthetic biologically active agents. A series of N-(5-(3,5-methoxyphenyl)-(thiazole-2-yl))phenoxyacetamide derivatives 6an–6bd were designed and synthesized, and their structures were confirmed by NMR and HRMS. Most of derivatives exhibited superior inhibition of Echinochloa crusgalli (E.c.) and Lactuca sativa (L.s.) seed germination