Abstract: This invention relates to the use of certain organo-titanium salts for use with fillers for the preparation of epoxy resins and other liquid thermosetting resins; the resulting filled resin compositions; and compositions of such salts and such liquid resins.The organo-titanate salts of the invention may be represented by the formulas:(RO).sub.z Ti(A).sub.x (OAr).sub.y, (I)roti(OAr).sub.3 (II)where R is a monovalent alkyl, alkenyl, alkynyl or aralkyl group having from 1 to about 30 carbon atoms or a substituted derivative thereof; A is a monovalent thioaryloxy, sulfonyl, sulfinyl, diester pyrophosphate, diester phosphate or a substituted derivative thereof; OAr is aroxy or a substituted derivative thereof; the sum of x, y and z equals 4; x and z may be 1, 2 or 3; and y may be 0, 1 or 2; or ##STR1## where A' represents a non-hydrolyzable group as defined above for A or an aryl group, B is an alkylene group (CR.sub.