Ensemble- entire costume of an individual, especially when all the parts are in harmony:
"She was wearing a beautiful ensemble by one of the French designers."
Manufacturers don't make matching dresses and coats very often anymore. I enjoy watching movies from the 1940's and 50's hoping to see them. The pieces of a true ensemble are made of the same fabrics. Quite often the dress matches the lining of the coat. All accessories match the fabrics of the ensemble.
If you would like to have an ensemble custom made, then choose the coat pattern first then choose a dress pattern with a similar silhouette. A skilled seamstress or tailor will be able to make an ensemble for you.