A series of 2,4-disubstituted-[1,3]-thiazoles (4a–p and 6a–l) was synthesized from 2-(aryloxymethyl)benzoic acids (1a–d) through a multistep reaction sequence in good yield. The structures of the new compounds were established on the basis of their elemental analyses, IR, 1H-NMR, 13C-NMR and mass spectral data. All the synthesized compounds were screened for their antimicrobial and anti-inflammatory activities. Preliminary results indicated that some of them exhibit promising activities and they deserve more consideration as potential antimicrobial and anti-inflammatory agents. The nonlinear optical (NLO) property of 4a–p was also studied. The compound 4n with 2-(3-methylphenoxymethyl)phenyl and 4-nitrophenyl substituents showed very good NLO property compared to other compounds and also the reference compound, urea.