Novel polyfunctional compounds and polymers are disclosed of the general formula ##STR1## wherein Q designates -X' or -X-.epsilon.-R; where X' designates ##STR2## where .alpha. is --OH, or --SH;.beta. is --OH, --SH, --NH.sub.2, --NO.sub.2, --CO--R.sub.2, --R.sub.2 C.dbd.N--OH, --COOH, -hal, alkyl, aryl, or aralkyl; halogen being chlorine or bromine;.gamma. is a non-interfering substituent;where .beta. and .gamma. may form together a hydrocarbyl ring system;where .delta. is --(CH.sub.2).sub.n -- or --SO.sub.2 --;where X is --O--, --S--, --NH--, --N.sup.+ R.sub.2 R.sub.3 Cl.sup.- or --P--;where.epsilon. is --(CH.sub.2).sub.n --, --SO.sub.2 --, --NH-- or --CH.sub.2 (O-CH.sub.2 --CH.sub.2).sub.n --; ##STR3## wherein the upwardly directed bonds are connected to the R polymer molecule and the downwardly directed bonds are connected to .delta. groups;n is an integer of from 1 to 15 or zero;R is a polymeric backbone, alkyl or aralkyl; andR.sub.2, R.sub.3 and R.sub.4 which may be identical or different, each designates hydrogen, alkyl, aryl or aralkyl. These compounds are useful as ion-exchange agents, extractants, biocides, flameproofing agents, fire retardants, metal polishing agents and rust inhibitors. Metals may be selectively extracted from solution thereof by means of these compounds and polymers.