Matching casual blazers and trousers

[Mr Tickle]

When you're pairing casual jackets and trousers is it a general rule of thumb that it's better to stick to similar materials across both halves - i.e wool trousers with wool jackets, cotton trousers with cotton jackets, etc?
It seems to me that often this makes sense - it would look strange, I think, in the case of something like a linen or cotton jacket and wool flannel trousers. But other mismatched combinations, like cotton chinos with a wool blazer, seem to make more sense.
Are there any set rules or useful guidelines in this area ?

 

[circumspice]

Nah. Cotton is probably found more often as a trouser fabric than as a jacketing fabric - certain true in fall + winter. Worry more about formality levels - I have some unstructured Boglioli cotton-linen sport coats that wouldn't work well with mid grey tropical wool trousers as they would be too polished for the top half