African city finally investing in Asian country (5)
I believe the answer is:
lagos
'african city' is the definition.
(Nigerian city)
'finally investing in asian country' is the wordplay.
'finally' says to take the final letters.
'in' indicates putting letters inside.
'asian country' becomes 'laos' (Laos is an example).
The last letter of 'investing' is 'g'.
'g' inserted into 'laos' is 'LAGOS'.
(Other definitions for lagos that I've seen before include "Formerly capital of Nigeria" , "African port" , "Nigerian city and port" , "Largest city and once capital of Nigeria" , "African city" .)