 <p>You would need to use the <a href="http://msdn.microsoft.com/en-us/library/ms132072.aspx">constructor for Dictionary</a> which accepts a custom <code>IEqualityComparer(Of T)</code> for your key type.</p> <p>Arrays, without a custom <a href="http://msdn.microsoft.com/en-us/library/ms132151%28v=vs.110%29.aspx"><code>IEqualityComparer(Of T)</code></a>, are not valid object types as keys to a dictionary (or other hash-based collection).</p>