Abstract: Synthesis of 2-(b -(aryl-X)styryl)benzothiazoles (2a - 2z) (X = 0, O, S) from aromatic or heterocyclic aldehydes and 2-naphthylmethyl-, 2-aryloxymethyl- or 2-arylthiomethyl benzothiazoles is reported. Phthalides 4a - 4f were prepared by Gabriel modification of Perkin synthesis. Products were confirmed by NMR spectral and elemental analysis. Prepared compounds were tested on herbicidal and growth - regulating activity. The semiempirical AM1 quantum - chemical method has been used to study an optimal conformation and heats of formation.