[Nightedge]

Connection can be followed by to or with; can I use to?

-He had close association __ those organisations.

[susan53]

I don't understand the question. Are you asking about connection or association or both?

If association/associate, it must be with. Here are some examples :

...her close association with Benjamin Britten
...the equations are associated with the possibility that...
Green feels reassuring and fertile due to its association with the rejuvenation

connection/connect can be followed by either with - usually for a mental connection :

We shall describe it in detail in connection with our second question
This exception may be connected with Hoijer's use of...
Certain concepts, which previously had been connected only with the king ...

or to - usually for a physical connection or occasionally to describe a relationship :

The running tunnels are connected to the service tunnel by cross passages
...it can be connected to a NEC 9800 personal computer.
...the harness that is connected to the lifting crane.

Mr Pocock has no connection to this family



I'd rewrite your sentence as one of the following :

He had close associations with those organisations for most of his life.
He was closely connected to those organisations for most of his life.
He had close connections with those organisations for most of his life.

[Nightedge]

Excellent answer. Thank you.