NOVELTY - Cyanine compounds (I) containing optionally substituted heterocyclic groups and a metallocene group containing a transition metal are new.    USE - The new cyanine compounds are used in pigments e.g. in optical recording materials and optical information recording mediums including CD-R/RW, DVD-RAM, DVD-R/RW. Some are useful for high-speed recording. The cyanine compounds may also be used, alone or with other materials, as a combustion improvement additive, a fluorescent labeling agent, visible light absorber of a solar cell, a filter of various information displays etc.    ADVANTAGE - The new compounds have improved resistance to light and moisture, good solubility, optical characteristics and thermal decomposition properties. Some have high sensitivity. The stabilizing effect of the metallocene group is available in the molecule so does not require mixing in. The recording is durable to laser light with little deterioration under long-term preservation in natural light or high humidity.    DETAILED DESCRIPTION - A cyanine compound of formula (I) is new.    L = 1, 3, 5 or 7 conjugated CH, optionally substituted by halogen or other substituent which may be bonded together to form a ring, or with a cyclic side chain across several C;    Y01, Y02 = group completing an optionally substituted heterocyclic ring;    Z = substituent of formula (II) or a group including it;    i = 1-4;    R01, R02 = H or optionally substituted alkyl;    Xr- = r-valent organic or inorganic anion;    r = positive integer;    u = number giving a neutral molecule; or    when R01 and/or R02 = group containing an anion, uXr- may be absent.    R03 = bond or connection group such as alkyl, -CH=CH-, -(CO)-, -NH-, -O-, -S-, -N=C-, -C6H4-, -(SO2)-, etc. optionally substituted by halo or another substituent;    R04, R05 = H or substituent;    M = transition metal such as titanium, iron, ruthenium, osmium or nickel    INDEPENDENT CLAIMS are also included for new intermediates of formula (XI)-(XIII) (see 'preferred compounds')