The synthesis of  cooligomers  of hexene-1 with indene in the presence of aquacomplex of aluminium chloride has been made and investigation of them in the composition of petroleum oils with the purpose of  preparation of basic oils with viscous-temperature characteristics has been carried out. The conditions, providing the  preparation of cooligomers  with the high yield and  the necessary value of molecular mass were found. The  composition  of  cooligomers and  its  molecular mass are  regulated in  dependence on concrete  requirement  to the  quality of the developed oil, that is the directed synthesis is conducted with preparation of  compounds with the given  exploitation  characteristics.