Azulenesquaric acid dyes of the formula ##STR1## where L is substituted or unsubstituted C.sub.1 -C.sub.12 - alkylene,R.sup.1 is C.sub.1 -C.sub.20 - alkyl, C.sub.5 -C.sub.7 - cycloalkyl or substituted or unsubstituted phenyl andR.sup.2, R.sup.3, and R.sup.5 are each independently of the others hydrogen or substituted or unsubstituted C.sub.1 -C.sub.12 -alkyl,with the proviso that when R.sup.5 is hydrogen the positions of the substituents CH.sub.2 --L--O--CO--NHR.sup.1 and R.sup.4 on an azulene ring may also be interchanged within a ring in either or both of the azulene rings, derived from azulene intermediates that contain urethane groups, are suitable for use in an optical recording medium.