Night-time suits block by modernist architect (7)

'modernist architect' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.

'night-time suits block by' is the wordplay.
'night-time suits' becomes 'mies' (I can't justify this - if you can you should give a lot more credence to this answer).
'block' becomes 'jam' (synonyms).
'by' is a charade indicator (letters next to each other).
'mies' after 'jam' is 'JAMMIES'.

Can you help me to learn more?