Innovative artists in revolutionary city flourish (3,4)
I believe the answer is:
new wave
'innovative artists' is the definition.
(term for a new artistic movement)
'revolutionary city flourish' is the wordplay.
'revolutionary' is a reversal indicator.
'city' becomes 'wen' (historical term for a large city).
'flourish' becomes 'wave' (synonyms).
'wen' backwards is 'new'.
'new'+'wave'='NEW WAVE'
'in' is the link.
(Other definitions for new wave that I've seen before include "1970s rock style" , "Style of rock music deriving from punk" .)