SPRINKLE gelatine over water in 1-cup microwavable measuring cup; let stand 1 minute. Microwave on HIGH 40 seconds or until gelatine is dissolved; stir. Let stand 3 minutes.
PLACE ricotta cheese, Neufchatel, sugar and cocoa powder in food processor or blender container; cover. Process until smooth. Gradually add gelatine mixture through feed cap, processing until well blended. Pour into crust.
REFRIGERATE several hours or until firm. Top with whipped topping just before serving. Store leftover pie in refrigerator.