When trying to build up lagging muscle groups, unilateral (single arm/leg movements) work is preferred over compound/multilateral movements for multiple reasons. Muscles that are lagging are that way for a reason; they are not being activated properly when performing the big compound movements such as bench/squat/deadlift and therefore stronger muscle groups take over to complete the lift creating muscular imbalances.
To activate these muscles, you want to isolate them as much as possible to prevent any other stronger muscle groups from taking over.
Not only does this mean you need to use isolation exercises such as cable flyes in lieu of bench press for the pecs, but you should also take it a step further by performing the flyes one arm at a time. This will ensure you are activating both sides optimally and the dominant side (right side for most people) does not take over.
For example, when attempting to isolate the lats by performing a lat pull down, it is better to go one arm at a time using a single handle in lieu of using the normal lat pulldown bar where one lat can take up the slack from the other, weaker, side.
This does not mean you must continue doing this indefinitely, just long enough to have a solid mind-muscle connection and the ability to activate the correct muscle groups in the bigger lifts.
That being said, I always recommend programming in some unilateral work for general physical preparedness.