  Two phenomenological models of $\Lambda$, viz. $\Lambda \sim (\dot a/a)^2$
and $\Lambda \sim \ddot a/a$ are studied under the assumption that $G$ is a
time-variable parameter. Both models show that $G$ is inversely proportional to
time as suggested earlier by others including Dirac. The models considered here
can be matched with observational results by properly tuning the parameters of
the models. Our analysis shows that $\Lambda \sim \ddot a/a$ model corresponds
to a repulsive situation and hence correlates with the present status of the
accelerating Universe. The other model $\Lambda \sim (\dot a/a)^2$ is, in
general, attractive in nature. Moreover, it is seen that due to the combined
effect of time-variable $\Lambda$ and $G$ the Universe evolved with
acceleration as well as deceleration. This later one indicates a Big Crunch.
