<p>The reaction mechanisms and structure–performance correlations of polymers used in coatings can be used to derive coating performance and promote innovation of coatings, but they are scattered in references. The paper first summarizes them. There are four important rheological issues in coating industry: one-point rheological test, how to select coating components, how to control application process, and correlations of rheological methods to coating performance. The paper provides solutions to the issues based on rheological references. Since it is not easy to prepare qualified phosphate films, inorganic–organic hybrid coatings have been developed and applied on metal surface without phosphating film, but the hybrid coatings usually use a large amount of solvents. The paper proposes a way to prepare VOC-compliant hybrid coatings composed of tetraethoxysilane sol below its critical gelation point and liquid prepolymers by dual-cure.</p>