  The Grundy and the {\rm b}-chromatic number of graphs are two important
chromatic parameters. The Grundy number of a graph $G$, denoted by $\Gamma(G)$
is the worst case behavior of greedy (First-Fit) coloring procedure for $G$ and
the {\rm b}-chromatic number ${\rm{b}}(G)$ is the maximum number of colors used
in any color-dominating coloring of $G$. Because the nature of these colorings
are different they have been studied widely but separately in the literature.
This paper presents a comparative study of these coloring parameters. There
exists a sequence $\{G_n\}_{n\geq 1}$ with limited {\rm b}-chromatic number but
$\Gamma(G_n)\rightarrow \infty$. We obtain families of graphs $\mathcal{F}$
such that for some adequate function $f(.)$, $\Gamma(G)\leq f({\rm{b}}(G))$,
for each graph $G$ from the family. This verifies a previous conjecture for
these families.
