A composition that can be used as catalyst in esterification, transesterification or polycondensation is disclosed, which comprises a stable solution comprising (a) titanium in the form of a titanium .alpha.-hydroxycarboxylic acid or its salt, (b) a C.sub.1 C.sub.6 carboxylic acid, and (c) zinc in the form of a water-soluble zinc salt, and (d) water; and substantially free of an alkanolamine, an aminocarboxylic acid, or combinations two or more thereof. Also disclosed is an esterification, transesterification or polycondensation process, which comprises contacting, in the presence of the solution composition, an organic acid or its ester or its salt with an alcohol, optionally in the presence of a phosphorus compound, an organic or inorganic toning agent such as cobalt acetate, or combinations thereof.