I had the exact same problem. I futzed around with the helper files and so on until I found that pod install did not install the frameworks correctly. I added the framework manually, then it worked.
So do the Podfile, pod install, use the ".xcworkspace" project - this is CocoaPods 101 - and then the steps below
My Podfile:
use_frameworks! pod "SwiftCSV"
1 - Make sure the framework is linked in the project/target.
- Click on the project -> Target -> General -> Linked Frameworks and Libraries and hit "+"
- Add the SwiftCSV.framework. Pods.framework was already added for me, so I guess pod install did that part correctly.
2 - In the swift file that wants to use SwiftCSV:
import Foundation import SwiftCSV // <===== I had to add this class SomeClassThatUsesSwiftCSV { var foo: CSV? }
For verification, make sure your project "Frameworks" group looks like this: 
Note: I am new to CocoaPods but I would expect that pod install does all this for me. That's the whole point of it, isn't it? But, it didn't, at least for me.