Just try like below,
flavorDimensions "dim1"
productFlavors {
flavor1 {
dimension "dim1"
applicationId "com.example.dim1.app"
}
flavor3 {
dimension "dim1"
applicationId "com.example.dim2.app"
}
flavor3 {
dimension "dim1"
applicationId "com.example.dim3.app"
}
}
For more details about build variant see this link