Colour of popular dye, initially, I blend (6)
I believe the answer is:
indigo
'colour' is the definition.
(indigo is a kind of colour)
'popular dye initially i blend' is the wordplay.
'popular' becomes 'in'.
'initially' says to take the initial letters.
'blend' becomes 'go' ('go' can be a synonym of 'blend').
The initial letter of 'dye' is 'd'.
'in'+'d'+'i'+'go'='INDIGO'
'of' acts as a link.
(Other definitions for indigo that I've seen before include "Blue-purple colour in spectrum" , "Ellington's Mood" , "Mood - (Duke Ellington)" , "Violet dye" , "Settlement; New Mexico native" .)