diff --git a/graflog.cabal b/graflog.cabal
--- a/graflog.cabal
+++ b/graflog.cabal
@@ -1,5 +1,5 @@
 name:                graflog
-version:             6.1.2
+version:             6.1.3
 synopsis:            Monadic correlated log events
 description:         Please see README.md
 homepage:            https://github.com/m-arnold/graflog#readme
diff --git a/src/Graflog/Logger.hs b/src/Graflog/Logger.hs
--- a/src/Graflog/Logger.hs
+++ b/src/Graflog/Logger.hs
@@ -75,6 +75,9 @@
 instance ToLog a => ToLog (Map Text a) where
   toLog = Dictionary . fmap toLog
 
+instance ToLog () where
+  toLog = dictionary []
+
 instance (ToLog a, ToLog b) => ToLog (Either a b) where
   toLog (Left l) = Variant "left" [toLog l]
   toLog (Right r) = Variant "right" [toLog r]