Prepare the whipped topping mix in a large bowl following the package directions, using skim milk and vanilla. Fold in the yogurt until well blended. Stir in the chopped black cherries.
Spoon a generous 1/4 cup cherry mixture onto the center of a crepe. Spread to within 1/2 inch of edge. Roll up crepe. Repeat with remaining filling and crepes.
Refrigerate crepes for several hours to chill and firm filling.
To serve, drizzle each crepe with 1 teaspoon chocolate syrup.