Asymmetric compounds having the formula: in which M is hydrogen, an alkali metal atom, ammonium or a cation formed from an amine: Xa and Xb are the same or different and each is NH.sub.2 ; NH(C.sub.1 -C.sub.4 alkyl); NH(C.sub.2 -.sub.4 alkoxyalkyl); N(C.sub.1 -C.sub.4 alkyl).sub.2 ; N(CH.sub.2 CH.sub.2 OH).sub.2 ; a group NH--Z--NR.sub.1 R.sub.2 in which Z is C.sub.2 -C.sub.14 alkylene or optionally substituted arylene, and R.sub.1 and R.sub.2 are the same or different and each is C.sub.1 -C.sub.12 alkyl or R.sub.1 and R.sub.2, together with the nitrogen atom to which they are each attached, form a morpholino, piperidino or piperazino ring; an aminoacid residue; C.sub.1 -C.sub.4 alkoxy; hydroxy-substituted-C.sub.2 -C.sub.4 alkoxy; ##STR1## and Ya and Yb are the same or different and each is a substituted amino group having both UVA and UVB-absorbing properties having the formula: ##STR2## in which R.sub.3 is CN; SO.sub.2 R.sub.5 in which R.sub.5 is C.sub.1 -C.sub.12 alkyl, C.sub.1 -C.sub.12 alkoxy, NH.sub.2, NH(C.sub.1 -C.sub.4 alkyl), N(C.sub.1 -C.sub.4 alkyl).sub.2, N(CH.sub.2 CH.sub.2 OH).sub.2, C.sub.1 -C.sub.4 alkoxy or hydroxy-substituted-C.sub.2 -C.sub.4 alkoxy; COR.sub.5. In which R.sub.5 has its previous significance; COOM or NHCOR.sub.5 and in which R.sub.4 has the same meaning as R.sub.3 or H, OH, C.sub.1 -C.sub.4 alkyl or C.sub.1 -C.sub.4 alkoxy and one of Xa and Xb can be identical to one of Ya and Yb, provided that one of Xa and Xb is different from the other and/or one of Ya and Yb is different from the other, and their use improve the sun protection factor (SPF) of textile fiber material.