Squarylium compound, optical recording medium using the same, recording/reproduction method and optical recording apparatus

A squarylium compound forming a metal complex,

• wherein the squarylium compound is expressed by the general formula (I) below:
• where R1 and R2 are the same or different to each other and each of R1 and R2 represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group;
• Q represents a metal atom having coordinating ability;
• q represents 2 or 3;
• R3 represents a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group;
• R4 represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group;
• R5 represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group;
• R6 represents a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a nitro group, a cyano group, or a substituted or unsubstituted alkoxy group;
• p represents any integer ranging from 0 to 4;
• and R6s are the same or different to each other and any adjacently located two R6s optionally form a substituted or unsubstituted aromatic ring together with two adjacent carbon atoms when p is 2, 3 or 4.