Cilj ovog rada je proučavanje fotokemijskog ponašanja derivata β-supstituiranog 5-klortiofenskog derivata o-divinilbenzena 1. Spoj 1 sintetiziran je Wittigovom reakcijom u dva stupnja, te je dobiven u obliku smjese cis- i trans- izomera koji su izolirani i spektroskopski okarakterizirani. Napravljena su preliminarna fotokemijska ispitivanja nakon čega je spoj 1 podvrgnut fotokemijskom ispitivanju, pri čemu su izolirana tri nova intramolekulska produkta. The aim of this work is to study the photochemical behavior of 5-chlorothiophene derivative of o-divinylbenzene 1. Compound 1 was synthesized by two-step Wittig reaction and it was obtained as a mixture of cis- and trans-isomers which were isolated and spectroscopically characterized. Prepared compound was subjected to photochemical irradiation, which gave three new intramolecular products. The new photoproducts were isolated and specroscopically characterized.