Went to pieces when penniless (5)
I believe the answer is:
broke
This clue could be a double definition.
'went to pieces' is the first definition.
'broke' can be an answer for 'went' ('break' can be a synonym of 'go'). I'm not certain of the 'to pieces' bit.
'penniless' is the second definition.
(I've seen this before)
'when' acts as a link.
Can you help me to learn more?
(Other definitions for broke that I've seen before include "Completely out of money" , "Bust - something to go for?" , "Skint" , "Ordinal number" , "With completely empty pockets" .)