The alternating copolymers of allyl chloroacetate (ACA) and allyl propionate (AP) with maleic anhydride (MA) and their organotin derivatives were synthesized by radical copolymerization in the presence of benzoyl peroxide as initiator in benzene at 70 degrees C and by the polymer-analogous reaction of anhydride-containing copolymers prepared with hexa-n-butyldistannoxane, respectively, and all were characterized. The alternating copolymers of monoallyl maleate (MAM) and tri-n-butylstannylallyl maleate (TBSAM) with styrene (St) and MA were also synthesized by radical copolymerization in methylethylketone in the presence of benzoyl peroxide at 60 degrees C. Photochemical reactions and structure-property correlations in the synthesized copolymers containing Sn, O=C, Cl and C=C (side-chain allyl or vinylene groups) were studied by using u.v.-irradiation with monochromatic light at 405 nm, Fourier transform infrared (FTi.r.) spectroscopy, differential thermal analysis (da.) and thermogravimetric analysis (t.g.a.). It is shown that unlike anhydride-containing copolymers which decompose easily upon u.v.-irradiation, the organotin derivatives doss-link under similar conditions. It is explained that the relatively low values of the quantum efficiency, phi(crl) = 0.035-0.11 mol Einstein(-1), of the photochemical conversion and the high photosensitivity, S = 6.8-21.6 cm(2) J(-1), for the organotin copolymers is provided by coordination-bound organotin fragments with sensitive CH2-Sn groups which transfer readily to the intermolecular carboxylate form under the conditions of photooxidation.