Dim hd As New Dictionary(Of String, Dictionary(Of String, String))
 
    Private Sub Test()
 
        ' Wert hinzufügen
        Dim d As New Dictionary(Of String, String)
        d.Add("Key12", "DerWert")
        hd.Add("Key11", d)
 
        ' oder auch
        hd.Add("Key21", New Dictionary(Of String, String))
        hd("Key21").Add("Key22", "DerZweiteWert")
 
        ' Wert auslesen
        Dim wert As String = hd("Key11")("Key12")
 
    End Sub

Those people who think they know everything are a great annoyance to those of us who do - Isaac Asimov