2-Mercaptobenzyl alcohol and 4-mercaptobenzyl alcohol were synthesized in good yields starting from thiosalicylic acid and p-toluenesulfonic acid, respectively. Poly(vinyl chloride) (PVC) reacts selectively with the thiol group of these bifunctional compounds leading to modified PVC with free hydroxy groups. In a second step the polymer chains can be partially crosslinked by reaction with hexamethylene diisocyanate. According to the degree of PVC modification, the network density of the resulting elastomers is freely adjustable.