I have been trying to export an Google Android Project from Unity so I can integrate an external library with Gradle. I am using : - Unity 5.4 Beta 18 OSX - Android Studio 2.1.1 I had first attempted to use Unity 5.3.4 & 5.3.5 but it was crashing on launch in what appeared to be an issue with the Unity IAP export when building a Google Android Project. A bit of research lead me to believe that the issue was resolved in the latest 5.4 Beta, however now I am getting a Multiple define error when building. Something signigant has changed as now I have a googleAIDL, googlePlay, and unity adsrelease folders. cupcakeTest common googleAIDL googlePlay unityadsrelease unityandroidresources Gradle Scripts The error the gradle build is failing on: Error:Error converting bytecode to dex: Cause: com.android.dex.DexException: Multiple dex files define Lcom/android/vending/billing/BuildConfig; Error:Execution failed for task ':cupcakeDigital:transformClassesWithDexForDebug'. > com.android.build.api.transform.TransformException: com.android.ide.common.process.ProcessException: java.util.concurrent.ExecutionException: com.android.ide.common.process.ProcessException: org.gradle.process.internal.ExecException: Process 'command '/Library/Java/JavaVirtualMachines/jdk1.8.0_25.jdk/Contents/Home/bin/java'' finished with non-zero exit value 2 When trying to remove this particular class it just moved onto the next one and repeat the error again. Is this a Unity issue with IAP and Ads or could this be something specific with my project? If I build just to an APK from Unity it works fine but then i cannot implement the external SDK. I can also export a test scene without Ads or IAP enabled and it does work in Project. I will try and enable those next to see if it is specifically these addons.