Abstract: There are provided substituted 3-phenyl-isoquinolin-1(2H)-one derivatives which selectively inhibit the activity of poly(ADP-ribose) polymerase PARP-1 with respect to poly(ADP-ribose) polymerase PARP-2. The compounds of the present invention are therefore useful in treating diseases such as cancer, cardiovascular diseases, central nervous system injury and different forms of inflammation. The present invention also provides methods for preparing these compounds, pharmaceutical compositions comprising these compounds, and methods of treating diseases utilizing pharmaceutical compositions comprising these compounds.