As @JánLalinský nicely explains, surface tension is measured between two fluids, while viscosity is measured within one. Say that you have a droplet of some liquid this means that if you change the surrounding medium the liquid-surrounding surface tension changes, while the viscosity of the droplet will not.

That said, if you keep the surrounding medium constant then there is indeed a correlation between surface tension and viscosity. Take a look at the table of alkanes below. You can clearly see that with increasing carbon chain length both viscosity and surface tension with air rise.

The problem is that this relation is not generally valid and only holds for relatively simple systems like alkanes with air. If you would for example measure the surface tension of these chemicals with heptane, then obviously this table will have a minimum ($0 \text{ mN/m}$) at heptane, but higher values of surface tension for both hexane and octane.

As @JánLalinský nicely explains, surface tension is measured between two fluids, while viscosity is measured within one. Say that you have a droplet of some liquid this means that if you change the surrounding medium the liquid-surrounding surface tension changes, while the viscosity of the droplet will not.

That said, if you keep the surrounding medium constant and very different from the liquids you're looking at then there is indeed a correlation between surface tension and viscosity. Take a look at the table of alkanes below. You can clearly see that with increasing carbon chain length both viscosity and surface tension with air rise.

The problem is that this relation is not generally valid and only holds for relatively simple systems like alkanes with air. If you would for example measure the surface tension of these chemicals with heptane, then obviously this table will have a minimum ($0 \text{ mN/m}$) at heptane, but higher values of surface tension for both hexane and octane.