C-60 forms aggregates in solution when the dielectric constant of the solvents exceeds some critical value viz. greater than or equal to 13. Further, for aggregation the C-60 concentration has to exceed some critical value. The aggregation process is reversible and the aggregates exist in equilibrium with monomers. Picosecond laser flash photolysis experiments indicate that the excited (S-1) aggregates undergo very fast relaxation without contributing towards the tripler formation.