A pigment-containing high solids coating composition is prepared from a curing agent and and ester diol which is a mixture of (a) 20-80 mole % of a compound having the general formula: ##STR1## where R.sub.1 represents the group formed by abstraction of the two carboxyl groups from maleic acid and/or fumaric acid and/or a cycloaliphatic and/or aromatic dicarboxylic acid having 8 to 20 carbon atoms and R.sub.2 and R.sub.3 may be the same or different and represent a hydrogen atom and/or a hydrocarbon group having 1 to 9 carbon atoms, and m is a number of 1-4, and of (b) 80-20 mole % of a compound having the general formula ##STR2## where R.sub.4 represents the group formed by abstraction of the two carboxyl groups from maleic acid and/or fumaric acid and/or a cycloaliphatic and/or aromatic dicarboxylic acid having 8 to 20 carbon atoms, and R.sub.5 represents the group formed by abstraction of 3 hydroxyl groups from a tri- or tetravalent hydroxy compound having 3 to 8 carbon atoms in the main chain, and X represents an aliphatic acyloxy group having 6-25 carbon atoms, and n is a number of 1-4.