The syntax you're looking for is not provided by the object that is being used with the dictionary, it is the dictionary collection itself. If you need to be able to use a collection initializer then you'll need to use an existing collection (like Dictionary) or implement a custom collection to house it.
Otherwise you're basically limited to:
var temp = new Pair[]
{
new Pair(0, "bob"),
new Pair(1, "phil"),
new Pair(0, "nick")
};